I disagree with the competitive gaming part, mechanical keyboards are also amazing just for the normal typing experience, coding, annoying sleeping partners, mashing enter when you are angry, etc. The ones marketed are usually targeted towards gamer though (Corsair, Razer, ect), but there are a bunch of non gaming-oriented models (Ducky, Poker, Das Keyboard, Keycool, customs..)
For your question, refurbished should be fine as mechanical switches are made to last for a while.
If you have question about switch types and such, I would direct you to the Wiki from the mechanical keyboard subreddit:
https://www.reddit.com/r/MechanicalKeyboards/wiki/index, we might even have a mechanical keyboard OT on gaf, I am not sure.
Be careful, this is an expensive hobby if you really get into it!