Anyone have the new TI calculator? My 89 is working perfectly, but it's so freaking slow in graphing the simplest surfaces. My only concern is the battery life. TI claims this new color doo-dad will last 2 weeks between charges. Provided that is true, that would mean that I would probably have to charge it every weekend to be safe, which I can live with. Does anyone have one? What do you think of it? I'm specifically interested in knowing if it's as intuitive as the TI-89 titanium, works similarly, processes quicker, and so on. I also have no idea what the difference is between the CX and the CX-CAS. Obviously the CAS one can use solve() and other algebra system functions, but that's it? There are 2 CX-CAS models on amazon with different prices!?