Key Features A summary of the most important features offered by each extension. |
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Our Rating Tooltivity's expert review score for each extension, based on hands-on testing and research. | 8.4 | 9.0 Winner in this category |
Total users Total active users across all major browsers: Chrome, Edge, Firefox, and Safari. | 1,000,000 Winner in this category | 8,354 |
Total ratings Total number of user ratings received across all supported browsers. | 8,796 Winner in this category | 70 |
Average rating Average user rating across all browsers, calculated from available store ratings. | 4.8 ⭐ Winner in this category | 4.5 ⭐ |
Entry Level Price The minimum price required to start using the extension. "Free" means a free tier is available. | Free | Free |
Chrome User rating and stats for the extension on Chrome browser. | ![]() 4.8 3.12 Average Chrome Web Store rating from the last 100 reviews 1.0M+Users Winner in this category | ![]() 4.8 4.64 Average Chrome Web Store rating from the last 100 reviews 7.0K+Users |
Edge User rating and stats for the extension on Edge browser. | - | - |
Firefox User rating and stats for the extension on Firefox browser. | - | ![]() 4.3 3.92 Average Mozilla Firefox Add-ons Store rating from the last 100 reviews 1.4K+Users Winner in this category |
Safari User rating and stats for the extension on Safari browser. | - | - |
Features Tooltivity's expert score for the 'Features' aspect of each extension. | 8.0 Merlin AI offers a variety of features including summarizing, writing, coding, diagramming and more. It supports multiple AI models such as GPT-4, Claude and Gemini and allows users to create custom AI chatbots and knowledge bases. The platform also integrates with the web and files in real time. However, some features, such as PDF summarization, are not as robust as those of specialized tools. It also lacks what we consider to be the important function of direct communication between AI and the current website. In addition, the function of direct communication between AI and the current website, which we consider important, is missing. ![]() | 9.2 The functional scope of GPT Reader is designed for a wide range of users and demonstrated many useful functions in the test. The voice quality is surprisingly good and offers a natural-sounding output. We particularly liked the comprehensive format support, which seamlessly processes everything from PDFs to web content. The control of the playback is also well implemented, making it easy to adjust the speed directly and individually. However, the function for downloading audio files stood out the most in the test. In theory, entire books can be converted and then downloaded as audio books. However, this was the only area where we had to make deductions, as the free ChatGPT version had limitations when processing longer texts or documents. Winner in this category |
Performance Tooltivity's expert score for the 'Performance' aspect of each extension. | 7.5 Merlin is generally fast and responsive, but it can slow down browsers, especially on older hardware. There are occasional bugs and crashes, though the team releases frequent updates and improvements. | 8.3 The performance tests showed a mixed picture. For shorter texts and paragraphs, GPT Reader processes content quickly and delivers a smooth rendering. The application is fast and reliable for typical use cases such as articles or short documents. Here we tested self-written summaries for learning purposes. However, we encountered significant limitations with larger files, as it is not possible to complete processing due to the limited number of requests. The option of pausing and then resuming would help here. In addition, the process takes a very long time for larger files; the extension needed around 40 minutes for around 75 pages of a PDF. The limitations of the ChatGPT API particularly affect the processing of longer documents such as entire books. This is currently only possible with a premium version of ChatGPT. Winner in this category |
Design Tooltivity's expert score for the 'Design' aspect of each extension. | 9.1 The design has a modern look and feel, with handy keyboard shortcuts and sidebar integration that make navigation easier. That said, the user interface can feel cluttered and overwhelming, especially for new users, and there are inconsistencies between the extension, web, and mobile versions. ![]() Winner in this category | 9.0 The design of GPT Reader is clean and professional, with an intuitive layout that makes navigation effortless. The fact that there is even a dark as well as a light mode shows that the different user preferences have been taken into account. The controls are logically arranged and easily accessible. Even though the extension is designed for functionality, the design is not forgotten. |
Value for Money Tooltivity's expert score for the 'Value for Money' aspect of each extension. | 8.2 The free plan is generous for light users, offering a substantial daily quota and access to a wide range of basic features. The Pro plan is competitively priced, especially when compared to the cost of subscribing to multiple separate AI tools, and unlocks unlimited access to all models and advanced features. However, the absence of a free trial for premium features means users must commit before experiencing the full capabilities of Merlin AI. Additionally, some users report that the query system—where different models and features consume varying amounts of daily queries—can be confusing or feel restrictive, particularly for those trying to understand how far their usage will go on each plan. | 8.9 Currently, GPT Reader offers a very good price-performance ratio, as all functions are available completely free of charge. We found no hidden costs or unexpected limitations in the free version. ![]() At the moment, however, it is a very good offer in the text-to-speech sector. Winner in this category |
Ease of Use Tooltivity's expert score for the 'Ease of Use' aspect of each extension. | 8.5 Getting started with Merlin AI is straightforward—installation is quick, and the onboarding process is simple enough for most users to begin using core features right away. However, the platform’s extensive feature set can be overwhelming at first, leading to a noticeable learning curve as users explore everything it offers. Some users have expressed confusion about how the daily query limits work, how different models are selected or switched, and which features are available on each plan. Occasional bugs and log-in issues can also disrupt the workflow, requiring users to troubleshoot or reach out to support. Overall, while Merlin AI is accessible, mastering its full capabilities may take some time and patience, especially for those new to AI tools. | 8.7 In terms of user-friendliness, GPT Reader scores very well. Users of all technical levels should have little problem simply converting text to audio. The user interface is self-explanatory, and all functions are displayed immediately. Winner in this category |
Security & Privacy Tooltivity's expert score for the 'Security & Privacy' aspect of each extension. | 9.3 Merlin does not sell user data to third parties and only uses data for core functionality. The privacy policy is transparent, but some users remain concerned about the amount of data collected and the permissions required. | 9.7 In our security analysis, GPT Reader showed a strong commitment to protecting user privacy. The extension only collects data from user-reported bugs and feedback. We appreciated the transparent privacy policy, where the user can read specific points. Winner in this category |
Conclusion A summary of our findings and final thoughts for each extension. | Merlin AI is a powerful and versatile tool that can really boost the productivity of a wide range of users. The integration of multiple AI models and functions into a single extension is ideal for this p However, Merlin is not completely perfect. We encountered occasional bugs, inconsistencies in the user interface and some performance issues. Pricing can also be confusing, and some features are locked behind a paywall.. Overall, Merlin AI is a good choice for anyone looking for an all-in-one AI assistant for the browser - especially if you value having multiple AI models and tools in one place. | GPT Reader is a promising text-to-speech extension based on ChatGPT voices. The easy-to-understand voices, combined with the fact that it is completely free, set it apart from conventional TTS tools. The extension can process various document formats. Both PDFs and copied web articles can be converted, but it has its limitations with longer texts. For example, a 300-page PDF was only partially converted in the text due to ChatGPT's limitations, which still resulted in about 2 hours of audio. The tool is very user-friendly and supports multiple languages. This extension is a must for anyone who wants to listen to texts. |
Our Recommendation | In our comparison between Merlin AI and GPT Reader, GPT Reader came out on top, scoring 9. Merlin AI is the most widely used, with over 1 million users and 9k+ reviews, but GPT Reader outperformed it in our review. User reviews for GPT Reader reflect our findings, while we rate Merlin AI lower than users do. Notably, Merlin AI has the highest user rating in the Chrome Web Store at 4.80, which is even higher than our rating of 8.4. There are some noticeable differences between these extensions, so it's worth considering your priorities and the details below.
If you want a quick recommendation, GPT Reader is our top pick. But as always, the best choice depends on what matters most to you. |