Honestly, TKD is more for younger guys.
It's the basics that will start you up for any other MMA.
Don't get me wrong I took TKD for 4~5 year and I know the masters and veterans are extremely phenomenal. Muay Thai is more of the shoot fighting while TKD focuses on kicks. Muay Thai usually only use Roundhouse/push kicks. Taekwondo use backick/hook-kick/spinkicks and such.
Edit: Oh yeah, lol I joined months ago and my first post is now,