UPDATE: As months have passed, I've been using this quite intensively. I never had any issue, until recently the creators decided to put serious limitations. Before that, I could use Claude 3.5 all the time, now I can only give it like 3-4 prompts and I hit the limit, and the app slaps me with "Want more? Pay for Pro". Right now, this app is utterly useless rubbish - literally you just have a few AI agents in one place, but that doesn't help much since you can use free tier for free on their own websites without paying for Merlin. So yeah, it was good when it was good, now I'd say it's not worth it.
I had mixed feelings buying this after reading a few reviews, but so far I haven’t been disappointed.

I didn’t notice the AI to give some very poor responses (I also have ChatGPT Plus so I know that sometimes it just gives a bad response so if Merlin does that I think it’s not necessarily developer’s fault).

I bought the 2nd tier with 12k credits. I knew that 5k won’t be enough, but I didn’t trust the app enough to buy 3rd tier. I only used it a few times quite intensively, I set it to use the newest GPT or Claude in some cases and it wasn’t as credit-hungry as I expected. But I’m skeptical about this because it’s possible the value of credits might change overtime as AI evolves.

But so far, it’s been a good purchase.

What I don’t like and what I’d change:
❌ you can set up a „project” in the app and feed it files with knowledge, but then when you open merlin extension on some other website, there’s no option to use that particular „project” that you fed with data. You have to open a new chat, upload files there and start from that.

So in this case it would be definitely nice to see some sort of more seamless integration between what the Merlin app offers and what you can use in the extension overlay on other websites.

Overall, it’s a good tool, I haven’t used it to the full potential yet, but I don’t think I’ll regret this purchase anytime soon.

Like I said, I’ve also got ChatGPT Plus that I use on my mobile and for the purpose of using my custom bot, but Merlin is great to use on the fly as I scroll through the web during my work, even to quickly sum up the tasks I need to do based on very long conversations with clients.

I’d buy it again, I didn’t give 5 tacos yet but I think it has a lot of potential.