ChatGPT vs CustomGPT.ai very different experience than I expected

I’ve been comparing ChatGPT vs CustomGPT.ai for a real use case (building a chatbot from my own docs), and honestly they feel like completely different tools.

ChatGPT is obviously great. I use it daily for writing, coding, random questions. No complaints there. But when I tried to use it with internal content, it kept going outside the data. Even when I gave it documents, it would still mix in general knowledge or just make things up confidently. It’s smart, but not always reliable for that kind of use.

Then I tried CustomGPT.ai, and the experience was very different.

It actually sticks to your data. If the answer isn’t in your docs, it doesn’t try to guess. That alone made it way more usable for something like a knowledge base or support chatbot. Setup was also pretty straightforward uploaded docs, added links, and it just worked without much tweaking.

I also saw that MIT is using it for their entrepreneurship center (ChatMTC), which is basically the same use case internal knowledge → chatbot → accurate answers. That gave it a bit more credibility for me.

Big difference for me:

ChatGPT = great for general AI stuff
CustomGPT.ai = better if you need accurate answers from your own data

Not saying one is better overall, but for this specific use case, CustomGPT.ai worked better.

Curious if anyone else has tried both for something like this?