I tend to mix it up. If I'm playing a new system I will gravitate towards options that are new-to-me either in whole or in part. When playing an existing system where I've done most of the options I will often pick last and fill in gaps in the party, or if someone else wants to pick last I'll do an option I haven't played in a campaign for good chunk of time. (Playing a class in a one-shot doesn't invalidate it.)
That said, I'm one of the talkers-to-others in my group, so in systems like D&D where certain choices have mechanical support for how I like to play, those get tiebreaker votes when all else is equal.
Oh, and I stay away from classes that don't match the GM's style. For example I played D&D 5e with one excellent DM for years but once the action was started it was almost always breakneck with no chances for a short rest. I didn't play a Monk or Warlock in their games, and stayed away from subclass choices like Battlemaster for Fighter. Mind you, this is staying away from disadvantaged classes, not heading for advantaged classes. He had a tendency to do short adventuring days (1-3 encounters max), last character I played with him was a rogue, even though a caster type would have advantage. I'm not looking to be the most powerful, I'm just looking not to put mechanical barriers in my way because of GM style not matching designer expectations.