Payback is just a clone of GTA which is a pisspoor game at the best of times, wasnt impressed by payback at all. If you're into GTA then id imagine you'll find payback great. As for me, i lost interest in GTA back in 1998.
The only game on there that really stood out and was truely worth keeping was noiz2a which can easily be added back on, and it was added back. As for supertux, being as im a linux user ive played it to death already on my main system and it isnt a bad little game at all, but not worth raving on about.
But yes, on a whole the NAND is full of crap.
EDIT: Forgot to mention vektar, thats an ok little game, im actually tempted to buy it, should it ever be a paid download that is.