Hey i'm normally over at the ps3 section, but as the sony rep came into where i work earlier, armed with a psp go, and i got to have a bit of a play around, i thought i'd share my experience.
My first impression was "

" that is small, and i couldn't imagine it being comfortable to play. But after a few minutes messing around with it i found it much more comfortable than my 1000. I think this was as it is more easy to get your fingers around, as it isn't so wide. However as it is much thinner (according to sony rep half a cm biggger than an ipod touch), it didn't feel overly secure in my chubby hands.
Size wise i was quite impressed even though the screen was smaller it did look higher resolution (even though its not). And the OLED backlighting (not proper OLED though) makes the image look much crisper than my 1000. On the other hand i don't think that the screen could be reduced any further without it having a big affect.
There were a few games installed, ridge racer 2 was the one that i tried, and the loading times are a significant improvement. Loading ridge racer in about 5-10 seconds

.
Although the look of it has grew on me and i now like it, i found that it does get covered in finger prints very easily, which when on the screen (as its hard not to touch it when you slide it out) can be very annoying.
Im not sure how much you guys know, as i say i don't browse here much, but he was telling me about the new app store thats for it (Im not sure whether these will all be games or whether there will be some apps as well).He also told me that people will be able to write there own stuff and submit it to sony for them to check through and publish. Like itunes (i thought that was very cool).
Whilst looking through the settings i had a look at the bluetooth settings and the setting up of the ps3 controller, however i didn't have the time and he didn't have the cables to set it up with the our ps3 so he has took my psn and is going to add me so he can tell me how it goes.
I can't really think of much else, but overall i had a generally good impression of it. My only major annoyance is the price, although its quite an update it isn't exactly the psp2 and for the price at the minute not really worth it if you already have a psp.
You probably lost interest a while a go but i thought i'd share my experience anyway.
Thanks
Adam