I was intrigued by the original Kick Ass, but not quite a fan after seeing it initially. After a second viewing I was better able to appreciate the odd sensibilities of the flick and the drastic tonal shifts.
If you enjoyed Kick Ass, I can't imagine you hating Kick Ass 2. Like the original it is genuinely sincere in its emotional content. It is still infused with a crazy energy and well shot, however where it is significantly worse than the original are a few plot elements used (rather lazily in my opinion) to connect the second and third acts.
The movie also is a tad more reserved with the violent content, nothing that happens is close to as brutal as the original, hell The Wolverine has a much higher on screen body count. That doesn't mean we're anywhere near gaining a PG-13, but it made the film a bit more fun for me. A gang rape was among the content cut from Millar's original book.
The cast is stellar in all areas and perfectly cast, though be aware Jim Carey has little more than a cameo. Donald Faison (Turk from Scrubs) also shows up as Doctor Gravity and is perfect with the little he has to do. Aaron Taylor Johnson and Chloe Grace Mortez are as kick ass as last time, but John Leguizamo feels wasted with the very little he has to do.
So in the end you've got a damn fine little film that would have been great if the plot was just a bit tighter.