THE SHORT VERDICT:
More often brisk and breezy than not, more often engaging and fun than not, and more often interesting and entertaining than not, The Three Musketeers is more than your average fusion sageuk.
This drama is a pretty bold attempt to adapt an age-old tale across mediums (novel to drama) and across cultures (French to Korean), while doing its best to retain the optimum crack ingredients that would appeal to a kdrama-loving audience.
Possibly due to its ambition, pacing across the show can be a little uneven, and logic gets sacrificed on more occasions than one might expect. Put on some generous Logic Blinders, though, and there are likely to be enough goodies in this one to make it worth your while.