Is the Prime truly ready for prime time?

[parisse]

I think you can't really compare bugs on the nspire CAS and on the Prime CAS, because the nspire CAS was a port of the TI92/89/voyage 200 CAS.
The programming language on the first nspire CAS was also the same as on the ti9x (TI Basic) except that I/O were not available, if my recollection is correct. Again, it was most certainly a port of the ti9x code.
By contrast, the Prime does not use old code from the HP48/49/49+/50G series.
Most of the new code on the ti nspire CAS was in the user interface. And I think that many ti9x/ti89 users found it difficult to learn. I know it's more difficult to learn a system when you are used to an other one, but it's probably the reason why TI made important changes later, like having a "scratchpad" calculator mode.
This just show that any complex system requires some time with real user inputs before it is widely considered to be really comfortable.