I have an N800 and an N810. I got the iGo Stowaway bt keyboard, and used it with my N800. I _just_ got my N810, and the keyboard is at work, so I haven't used it with the keyboard... but there are definitely times on the N810 when I wouldn't mind having the larger keyboard for typing (ex: I'm likely going to move all of my IM'ing to the N810, and it's fine to have light conversations via the thumb keyboard, but there have been a couple conversations where I really wish I had a full size keyboard; same with taking lots of notes in a meeting, etc. -- there are always going to be cases where the speed of two handed, instead of two thumbed, typing will be a win).

So, I'd still say it's worth buying. Esp. if you can still find the iGo for under $50 (I think Amazon had it that cheap 3 or 4 weeks ago, that's when I bought mine, I just don't remember if it was Amazon or not).

I can't compare it to the PSP though. I don't have one.

Also, it's not too late to stick with the N800 -- a lot cheaper now, just buy it from one of the places that has them for cheap.