Before I start I wanna make it clear this is ONLY the PS2 games, I don't think its fair to include the PS3 games since Jak & Daxter doesn't have any.  I always thought of these three games as some of the best platformers on the PS2, but the question is which one is the best?  Personally I love them all, but if I had to choose I gotta go with Ratchet & Clank.  It was the first one I tried and I loved it, its one of my favorite franchises and every installment on the PS2 just kept getting better and better.  I really like the humour in the game and the gameplay is amazing to me.  So which one is your favorite? 

Their all good but Jak and Daxter is my favorite.

Still hoping Naughty Dog hasen't given up on Jak & Daxter 4.

Ratchet ≥ Sly > Jak

Ratchet that good, he is twice in the rank

As long as they don't make it super realistic like they were about too then I hope they make another. In a perfect world for me ND would finally make a handheld game and make Jak 4 for Vita but theres a 0% chance of that lol

Ah, the best of the Sony exclusive franchises that actually appealed to me greatly. I will give this to Jak, since 3 was too awesome. Sly and Ratchet are in some kind of tie, it's really hard, only played one Sly.

Never likes Sly Cooper, and Jak and Daxter was alot of fun. I just really enjoyed the Ratchet & Clank games better

And for me, both Ratchet & Clank: Up Your Arsenal and Jak 2 are my favourite PS2 games, but if I have to choose, i'd pick Jak and Daxter, it does better as a game with an well done story, something that, in my opinion, the first two R&C lacked.

About Sly, it does very well as a platformer but I just don't adore it.

Overall, the "Future" trilogy of R&C is way better than both Sly and Jak games, but it is from the PS3.

A tie between Sly Cooper and Ratchet and Clank.