I had a Casio as well because, IIRC, it was the only thing the shop had. Eventually I had to also get a TI because it allowed using imaginary numbers in a matrix operation. Not that that was used in more than one course after all. But I grew to like it and even had an emulator for a long time on my first smart phone.

But yeah, Casio was definitely more friendly and polished in UI, but dumber. You could only use "wizard" type things and pseudo gui clickies while the ti was crude and text-heavy but let you enter just about anything anywhere and seemed more symbol and language oriented. Which one was nicer in use? I guess it would depend on how much of that language you could memorize. Or browse a cheat sheet for.