I'm coming from a Crackberry Curve and have tried the MyTouch 3G, rooted it and installed a custom firmware for 10 days before I returned it with it's original firmware again. The onscreen keyboard is no good to run a ssh session.
I'm very pleased so far with the N900. Yeah, it might have some shortfalls, but so did Linux about 15 years ago when I started with kernel 0.99 I'm definitely a sucker for the command line.