J&D1 was pretty much a standard platformer that was enjoyable at the time but probably hasn't aged too well.
Jak2 went in the absolute opposite direction and incorporated a new "edgy" style and a lot of GTA type of missions. However, a lot of the efforts to make it less cutesy came off as being really calculated, and driving around the city and pulling missions could be infuriating due to some really bad controls on the vehicles.
Jak3 reigned in the best stuff from 1 and 2 and had some great platforming and driving. It cut down on the whole angst factor but kept the weapons and some of the locations from 2. I found this one to be the best of them since it offered some good variety with the controller-throwing problems in the second one.
those types of games don't sit well with me, seem too boring. Don't know why I can't get into them, though. Maybe they remind me too much of a kid game. I want blood, guts, guns, DEATH!
They were all great, but Jak 2 was easily the best. My opinion might be a bit skewed because it was the first one I played, but I still like it the best. Regardless though, you can't go wrong with any of them. Those three are the best platformers ever made.
I got Jak 3 when I got a second-hand PS2 recently. It was great fun for awhile, but I got up to a shitty escort mission and gave up after about 20 tries. If I was just contending with the robots, it'd be fine, but wrestling with the camera aswell and robots popping up behind me to kill the guy I'm trying to protect = not fun.
Also, I really wasn't expecting it to have a plot, or a run-on one at that. Never played the first 2 and it never once stops to introduce any of the old characters, let alone what the hell's going on.