I've seen that kick in an mma fight...brutal.Its very defensive, and after a Muay Thai fighter's kick the thing I fear the most is a copoeirista's sweeping round kick, and capoeira also has the advantage of turning you into a beast on any disco/dance floor.
Main problem I have with capoeira is that all that dancing (ginga) can wear you out if you lack the physical shape to maintain it and you don't take your opponent out quickly enough.