I replay it for the levels. I like to replay Leon Chapter 1 because it has a lot of atmosphere.
Being in a city in the wake of a zombie outbreak sure brings back memories, especially with the rookie cop and gunshop segments.
Jake Chapter's 2-3, 3, and Chapter 5 are fun to play. Messing with Ustanak, sneaking around with nothing but a stunrod as Sherry, and the tension of running away from those Regenarator wannabes while waiting for those stupidly designed elevators to ascend and rotate is quite fun.
No Hope is a pain but can be fun sometimes. Just to be on the safe side, have an Infinite ammo if you want to cheese through a really hard part or if you want an "I WIN!" button
I hate how my AI Jake doesn't help me when I get grabbed by a Regenarator and even with Breakout, I swear, it's impossible to break free. Oh, and your health apparently doesn't get restored on the last checkpoint so if you get grabbed with on health bar left, be prepared to wait for 15 agonizing seconds as you watch an incarnation of how Xenomorphs spread.
Also, Sherry+ vents= DAT ASS! XD
--- "Dating Yukari Takeba is, like, the closest thing to dating Michelle Ruff, so I don't see the reason why not."- My brother XD
Both. It just depends on what I'm in the mood for.
Most played: Leon's because he's my favorite and his campaign has the most 'traditional' atmosphere.
Runner Up: Jake's mainly for Sherry. I love the direction they've taken with her character. Their story is a lot of fun because you get to see what Sherry's grown up into and we get introduced to Jake.
3rd: Ada's. I like Ada but a lot of her story is running around on ships and most of her last chapter was in a helicopter. They could have done so much more with her campaign but I just felt it was lacking.
4th: Chris'. I didn't like what they did with his character in RE6. I felt he deserved more than a RE5 emotional re-run.