CASIO 90+E vs HP Prime

[Steve Simpkin]

"What impressed me badly is for example how limited is the 3d graphing functions. You just select a template from 5 and that's all. "

Try the Graph3DP 3D graphing app by KermMartian. I find if more flexible.
https://www.cemetech.net/programs/index....ile&id=727

This is no Prime killer but the going price of around US$60 (target.com), it is quite a bargain.