Git's real kryptonite right now is indeed giant repositories (think GB size files)
People will yell at you about "you shouldn't version control binary files". And if the files are unchanging, they're right...
However, whatever the file size, if a file is changing frequently (you "open it", "change some stuff", and "push save" on a regular basis), there are - literally - multiple versions of that file. By definition, you need version control
Not on Windows
If you don't have to deal with Windows, your answer is easy. There's simply no competition: git-annex is what you're looking for; the no Windows thing sure does hurt though
On Windows
For those of us stuck on Windows, this stackexchange thread and this stackoverflow one both have a few good pointers, but no silver bullets :(
My biggest hopes currently are git-annex possibly making it to Windows, or bup becomming less "bleeding edge"