I have a Pandora and I love it for what it is. A gaming handheld / mini PC. The Pyra will be pretty similar (better specs though) and will be the successor of the Pandora. Not sure yet - I might buy a Pyra too.
So great products - and it would be very nice to be able to use mobile internet (3G/4G whatever) or even use it as a phone when you have nothing else. That said, it is not a phone and never intended to become one.

The N900 is a phone / Mini PC and the only successor is the NEO900. Not sure if I will buy one but I hope those guys will make it a success.

That said, if you are looking at it from the mini-pc angle (I started using my N900 only as an emacs mini pc) the Pyra will be an excellent - albeit bulky - choice.