>I've noticed that most devs seem to have strong opinions one way or another.

I've personally noticed that most devs don't have an opinion either way since they don't use subtrees nor submodules.

I don't know what subtrees offer but using submodules has been very pleasant once you know how they work. For example if you version control your .vim I think that adding submodules for extensions is way better than cloning them inside your .vim.

I look forward to having the opportunity to use subtrees.