First any PSP you get you want on 6.35 or lower, you don't want to pandora hack if you can help it.
Second I got my go a couple of weeks ago it was on 6.31
Semi hack is not annoying at all! You just have to activate chickhen which reboots the PSP and its done in a matter of 10 seconds.
Advantage is double the RAM of PSP 1000 and it won't affect most games, but KH:BBS comes with a 16/32 bit colour option which i assume is for slowdowns on 1000 and I've played "fired up" with both a 1000 and GO and on multiplayer I can tell you it's a big advantage when the 1000's vehicle is winding hopelessly and the GO's is running rings around it.
TL;DR GO's semi hack is no fuss whatsoever unless you don't have 10 seconds to spare. Comes with 16GB memory which costs a tidy sum separate for PSP 1000 and has double the RAM.
If it's cheaper then go for 1000 but I recommend GO.
Plus you can trade in PSP GO for £60 at gamestation whereas you might get £30 for base pack if that.
P.S check firmware before purchase always, but all 1000's are hackable if you can be arsed with pandora battery hack.
EDIT2: also I thought 3000 and Go's screens were the same. Turns out GO's is much brighter in comparison. And 3000's is even brighter than 1000 AFAIK so
!
EDIT3: I've even noticed slowdowns for 1 or 2 seconds on KH BBS when in a boss fight and he fires 20-30 bombs out at once, and this is on GO, in full colours. But I KNOW for a fact that in AdHoc mode with me on GO, uncle on 1000 and cousin on 3000 it's my uncle who loses which is down to the slow speed of gameplay. I mean, you don't see any framerate drops on the game you just move incredibly slower than the rest of us which is weird as hell. (No issues really on singleplayer because all the competition will have the same problem
)