Do a search on the forum, there is a lot of information about both and even a recent thread discussing the similarities and differences between the two.
For both services, you have to keep mind that you are an officer first and an aviator second. With that in mind, the path to getting your wings is long and arduous and you have to keep in mind that your dream of being a pilot could end at any point on that path, often for reasons out of your control. And even then, becoming a fighter pilot is no sure thing, the vast majority of Aviators in the Marines are helicopter pilots and I believe the majority of Navy Aviators are helo now too. The vast majority love what they fly, no matter what it is.
Good luck.