I'm a bit of an Arthurian nerd, so feel compelled to watch anything like this. My verdict on the first two episodes are that there were too many lady bits on show, Merlin was too creepy (both of which they were probably going for), the fighting wasn't very good, and some of the continuity was terrible (the landscapes, outfits, and blood on faces in particular). It was all a bit fluffy and smelled like The Tudors, but I still rather enjoyed it and I'll no doubt watch a few more episodes.
It also made me want to watch the far superior Monty Python and the Holy Grail, never a bad thing.