Some answers to your question are at
http://www.nsbasic.com/ce/info/Comparison.html
NSBasic has the obvious advantage that you can code on the go without requiring a host computer, but the disadvantage that it's not free
I don't really like either of them for serious development, as both require runtime files and compile down to non-native code however nsbasic in my experience is a lot more performant, and has more features. Perhaps my dislike is just snobbishness, I dunno
What are you thinking of writing? I'd still say that the best development environment for HPCs is Embedded Visual C++, either v3 or v4. For compatability, use v3 and develop against the HPC Pro sdk.