When I was a competitive martial artist, Muay Thai was part of my regular routine. It's excellant for all kinds of things, but for me the most beneficial aspect was the shin blocks and effectiveness in extremely close quarters. Especially in MMA style fighting, Muay Thai can be effective for fending off leg kicks and body kicks if you really master shin blocks. If you condition your shins and muscles properly, it's likely your opponent will hurt their foot and leg with a well timed shin block.
I studied traditional muay thai, and it was somewhat brutal, compared to some other martial arts out there. Drills to condition the shins and muscles surrounding it to accept blows were to essentially kick a makiwara (I don't know the english term or official Muay Thai term, but essentially a wooden post wrapped in straw) over and over again. More advanced students would strike each others shins with a baton wrapped in the same straw in drills.
There's a lot of pain involved, but a lot of reward, as well. Its been almost 5 years since I have been in it, however, so things may have greatly changed.