I bought a TI calculator after reading Americans rave about them, and I used it for a while to try and get the hang of it, but the interface really sucks compared to my Casio, so now I just use the Casio. I don't see what's so great about TI calculators.
You can compare the Casio interface with a web-mask.
Plug in p and q and get the solutions to your quadratic equation. If there is no mask, you're out of luck.
The TIs instead work on the basis of functions like from a programming library. Their equivalent might be a BASH shell with pipes. That is cumbersome on the first glance but incomparably more powerful. You can chain an arbitrary amount of functions.
I once finished a 3-hour exam in 20 min since most of the questions could be translated to a like 5-lines long function-chain that took like a minute to calculate on 10 MHz but were correct in the end.
