Preferred plugin installation method

For anyone who cares to comment, how are you installing plugins (from
github, 99% of the time) into your projects, and why are you using the
method you're using? I'm assuming you're using git to manage your code.

Specifically, are you doing something like script/plugin install
git://github.com/ajsharp/mass_assignment_murderer.git (assuming you're
using rails 2.1)?
Or, are you doing something like git submodule add
git://github.com/ajsharp/mass_assignment_murderer.git
vendor/plugins/mass_assignment_murderer? Or are you just doing a git
clone or something? (And yes, that was a very shameless plug for a
little plugin I wrote)

I've never really gotten a good feel for what the best practice is for
plugin management, so your answers and input are greatly appreciated.