I tend to think it’s a matter of organizing. It really doesn’t matter if you have no intention of being involved in the parties. Voting isn’t impacted, except primary voting, so if that’s all you’ll do, register where the primary helps (probably GOP for libertarians).
If you plan on actually being involved, go with where you can either shift the party platform to your ideas on select issues, or go to where there’s already a platform you support and think you can materially help.
(Editorial comment by Ford).