I got BF4 because I've liked every Battlefield game released, especially since Bad Company 1.
BF4, for anyone wondering, is pretty much BF3.5: For Real This Time. Returns Battlefield to its Bad Company roots with destruction and better map design, no more awful class balancing, and the campaign isn't the worst thing I've ever played. I'm actually having fun in multiplayer now even when I'm horribly losing, unlike before where I would rage at getting laser-gunned instantly by the ninetieth Assault player with his 100SS M16A3. If you liked BF3, get it, but if you haven't, you've already made up your mind about it.
Course, some of the funness in BF4 might come from it being new and no one having any idea what to do best. Give a month or two and there's going to be less constant shooting or more of everyone using the same overpowered God Gun. I'm going to miss my easy headshots when everyone starts camping more. (By the way, the Snipers in that game shoot like an absolute DREAM.)