I'm a fan of the CFS series. I've been in an online Flight Sim Squadron based around CFS/CFS2 for 3 years now, so I have a lot of experience with each.
CFS2 has some incredible eye-candy, especially when compared to the original. The cut scenes in between missions are cartoonish, but this really isn't a detractor from the game, it's just a different type of carry-over perspective.
I'm not a pilot in real life so I can't tell you that the Corsair doesn't fly right, but in comparison with CFS and other flight sims, the planes in CFS2 feel sluggish. It feels like it takes forever to get up to speed and altitude. Turns seem to take forever to complete and you lose a lot of speed doing basic maneuvers.
In CFS2 offline my biggest complaints are you get kept out of the biggest battles in the pacific; Pearl Harbor, Midway, Coral Sea, Santa Cruz, etc...
The end of the single player campaign is down right horrible. Your player just "retires", there is no sense of closure. After playing for hours and through several missions, you just "go home", and that's it. That was very disappointing to me.
Online, I don't like the fact that you can't set your plane levels how you want. You will always have 100% fuel and ammo regardless of the settings. After you die, you always seem to respond a huge distance from the main fight, taking forever to get back into the battles. There are patches out by 3rd parties that fix some of these problems, but still it should have been part of the original game.
Biggest complaint: Because of MS using such open architecture allowing 3rd party add-ons, cheating is very rampant online. It's hard to find a game without at least 1 person cheating in it. I'll be nice and say that 70% of the people online play honest and fair, but that 30% that doesn't really take a toll on your patience.
Overall this is a fun game but has several downsides for hard core simmers. The graphics are great, but the game feels sluggish and unrewarding. The addition of 3rd party add-ons help out, but still leaves a lot to be desired.