Pros: Provides much better temps at higher clocks under full load. Easy to install. No need to piece together multiple parts.
Cons: Idle temps seem to sit higher than my old Hyper 212+. Operates better on intake instead of exhaust, not good if you have a GPU that dumps in the case.
While the H70 was, at it's time, the top-of-the-line AIO cooling solution, it was far from being the best cooling solution, period. At high clocks and full load it kept temps down much better than my Hyper 212+ on my i7-920 but when it came to idle temps it didn't really do much better and seemed to actually increase my temps by about 5 degrees. It did perform quieter than the air setup simply because I could have the fans blowing at slower RPMs and get better temps when dealing with high load situations but the higher idle temps left my fans running fast at idle than when the 212+ was cooling.
The Corsair H70 is a great pick for people that can get it cheaply but I wouldn't buy it if you need something that is going to be cooling more powerful chips or if you need better idle temps with lower RPMs.