I've always loved the art-style and humor from the first game since I first played it on PS2 and in that respect the sequels are certainly more of the same. I never played Jak II or Jak 3 back when they released.
Anyway, replaying Jak & Daxter: The Precursor Legacy was a nostalgic trip down memory lane. I personally thought Daxter was at his funniest here because he didn't seem as obnoxious compared to the sequels, and so when he did speak his humor stood out more. The environments are lush and varied; beaches, lava pits, dark spider-infested caves, snowy mountain-tops, an underwater "lost city", and so on. It isn't really too story-heavy but what story there is, is semi-entertaining and interesting enough to follow. The first game is mostly a straight-forward 3D platformer collect-a-thon with your occasional boss fights, vehicle segments and cutscenes. But it's a vibrant, colorful and quite enjoyable one. Most fans of this series I've heard from seem to regard this one the highest.
Jak II I just recently beat (and platinum'd) so it'll probably be the freshest in my mind and easiest to review now. The game actually has a decent story that has a few twists and eccentric characters. The platforming is also still great when there are platforming segments. It seems to have adopted several elements from the then popular GTA games like GTA III or Vice City. You travel to icons around the city of Haven to start missions. They introduced weapons in the form of guns, which overall makes the sequels actually feel more like shooters a la Ratchet and Clank than platformers, and you now have a "Dark Jak" form which you can activate once your dark eco meter is filled. This form allows you to hit harder and do a few special moves that you can purchase via "skull gems" dropped by most metal head enemies. Sadly, most of the game's strong points end there for me.
The city hub in Jak II feels far too padded out and is more frustrating to navigate than being fun. The checkpoints for missions are also very unforgiving, often times requiring a complete do-over if you manage to die. This can be overcome with some trial and error but it can just grate the nerves if you've almost completed a mission, and you just manage to slip up at the end and fall off into an abyss or lose your last sliver of health. Racing was also a pain, as were some of the combat-focused missions such as one requiring you to get to a certain location while endless swarms of cops and turrets descend upon you. Or killing three huge robot vehicles headed towards your base before they get there. There are combat/weapon tricks involved for most of these though, and I'd recommend looking up video guides if/when you get stuck. Some other missions weren't really that hard however, in contrast to what a lot of people led me to believe. The "protect the NPC" or escort missions were actually pretty easy for me. As was the on-rails turret mission which I managed I think on my third try. It just required some patience and very quick disposal of enemies as soon as they appeared. I ended up using an "Orb glitch" to achieve the full 286 required for the Platinum trophy, which otherwise would be near impossible for me seeing as you would have to get "gold" in the shooting ranges among other mini-game type stuff. Overall a solid game but due to most of it being frustrating I personally couldn't rate it any higher than about a 6/10. The first game was just more enjoyable for me and stayed true to traditional platforming.
I've only just started Jak 3 and so far, as many people will tell you, it's mostly easier than Jak II simply because of the more lenient checkpoint placement. Gameplay mechanics and mission structure are still very similar to Jak II, however. This one, so far, seems to have quite an emphasis on vehicular gameplay; races galore, driving through the big desert to rescue NPC's before the time limits run out, and so on. There's still platforming sprinkled in here and there but it just seems to be a more "driving-focused" game. I hear it gets better and eventually blends in more platforming as well as combat missions but having to drive around or ride those large birds everywhere can kind of feel repetitive. The story is otherwise solid enough and characters well-done. But I'm more eager to see what the game has to offer besides driving, and the occasional boss fight missions.
I will say, and I almost forgot, I actually enjoy the few sections where you get to play as Daxter. Aside from running from the spider in Jak II which was highly frustrating initially, the other parts where you get to play as him in Jak 3 are, thus far, varied and spicen up the monotony of all the driving and shooting you do as Jak.
Anyway, like I said at the beginning of this "review", I love the art-style and platforming (when it's present) of this series so much that I have to rate it five out of five stars here on Amazon. For all its shortcomings, it's certainly a unique series. I also have the Ratchet and Sly collections for PS3, but they haven't really grabbed me yet based on trying out the first games in each series. Jak & Daxter was just likable to me from the get-go so I tend to prefer them out of the three series. Maybe that'll change once I give them another shot after finishing up Jak 3.