I know this is silly and probably more than a little undeserved, but I stay away from java, JARs and WARs like the plague. I barely use Java for anything anymore, and I know 8 is great, but I'm just not comfortable running that/taking care of it.
I've actually rolled up my sleeves and written some login adapters (for internal use) in gitlab, and I'm much more comfortable writing ruby in rails than I would ever be writing Java. Again, this is probably a stupid opinion, but until I see the Java light, I don't think I'll be back to it.
Also, gitblit looks nowhere as good as gitlab (or even gitorious) does. Neither does gitbucket -- they don't have the polish that I see on other solutions... Yeah it's a really fickle point, but I want to reward groups that also prioritize design/visuals in their projects.