I used it for a few hours earlier - I threw two technical heavy books at it, ones that normally I'd procrastinate on due to their complexity relative to my knowledge.

I'm pretty sure this is not the intended use of the app at least in deep dive mode (I used up 75% of this months tier 2 credit on just these 2 books) but it made wading through tricky concepts a lot easier.

I like the split screen mode reading the books and running queries simultaneously.

I wonder if there could be a bit more interaction with the source file and the deep dives - Perhaps that's what the table function is for. I don't dare try that feature right now just in case i burn through my remaining 25% credit by accident.
It would be useful to have some PDF editing functionality - somewhere between basic functions found in a PDF app, and more advanced stuff found in something like Liquid Text .

I found highlighting text buggy when trying to use the summerize/explain/custom instruction feature - it clips the highlighted selection making the output wrong.

I'm looking forward to more reading soon.