Your diffing doesn't suck! That alone is really valuable. What really sucks on Windows is merging: there are very few products that deal with merging at a basic competency level (the git merge markers usually wreak havoc).

One criticism: that jgit tab needs a serious UX pass. It's extremely scary looking to someone who has never used it (me).

That being said, I'll be keeping a very close eye on your kickstarter. Very close.