The sad difference between the Nspire series and say, the TI-89, is that the calculator is incredibly crippled in terms of usability. I've never been more frustrated with any calculator than the Nspire CAS. Much like the iPad makes a good media consumption device, the Nspire seems like its purpose is also simply to consume electronic lesson plans distributed by a teacher.
Actually using the Nspire is maddening how many button presses it takes to accomplish simple calculations. The trig functions are hidden behind a single button, which takes multiple presses or using the navigation pad to navigate to the correct function. Trying to access the solve function is also several menu levels deep with no easy shortcut.
I haven't seen the Nspire CX screen, but the black and white screen of the current models is an abomination completely unreadable under normal indoor lighting conditions. The backlit LCD on the CX series would correct this problem, but then the power consumption jumps, necessitating the use of a rechargeable lithium ion battery, which of course has a limited lifespan before replacement is needed.
TI spent more time locking down the calculator than addressing usability. With just a couple buttons, you can accidentally put the Nspire series in press to test mode, which activates a flashing red led and restricts access to any 3rd party programs along with removing access to built in functions. To get out of press to test requires connecting to a computer or another calculator.
It's true than the Nspire CX is a stunning looking calculator, but all joy ends there sadly. With TI playing a cat and mouse game with developers, they have also alienated an entire enthusiast community.
Aside from the improved hardware, the Nspire series is a significant step down when compared to the HP50g or even the TI-89. If the Nspire series encourages HP to release a new product, at least there will be some benefit to us. Hopefully HP can see beyond the glitz that TI has included just for show and provide a legitimate tool that enables one to quickly and efficiently get the answer for which he is looking.