"Camelot" is a bit of a mixed bag. It has its good points, to be sure, but it also has its bad points, and whether the negatives outweigh the positives is something that I think is going to be down to individual tastes - already the series is receiving rather mixed reviews. So let's break this down.
* The cinematography. Money has been poured into this production and you can really see it here. Sweeping vistas, use of CGI, even the title credits look slick and are thematically and artistically very similar to "The Tudors" and "The Borgias" (not too much of a surprise as some of the same people also worked on "Camelot" and apparently the show was aiming to follow in that vein).
* The cast. Again, one can sense the big spending here. You've got Eva Green as Morgan Pendragon, Joseph Fiennes as Merlin, Sean Pertwee as Sir Ector, and James Purefoy as King Lot. All bring a lot to their roles, putting in layered performances that bring the characters to life. Some of the lesser known, younger members of the cast such as Peter Mooney also succeed in pulling out some good, solid acting here.
* The show isn't afraid to be dark. Unlike the BBC's "Merlin", "Camelot" is much darker and contains a good deal more blood, sex, and language - most definitely aimed at adults, not children. If you felt that "Merlin" was a bit too wet behind the ears, you'll appreciate the darker "Camelot".
* Jamie Campbell Bower has been miscast as King Arthur. Arthur, who is after all the hero of the Arthurian legends, seems to be a whiny teenager here, cast on the basis of his prettiness. The character comes off as basically decent, but careless, reckless, driven by lust, sulky, and totally ignorant of the consequences of his actions. Not exactly kingly material, and not a patch on the legendary heroic Arthur; brave, thoughtful, wise. Also the writers have flipped around the whole Lancelot/Guinevere tale so that in "Camelot" Arthur is "in love" with Guinevere, a woman married to one of his knights named Leontes. I say "in love" but it seems like simple teenaged lust to me - Arthur's off declaring his undying love within a day of knowing Guinevere. My guess is the writers took this choice because they want to make Arthur seem like more of a hero and the guy who gets the girl, not the cuckolded victim as in the legend. The problem is it makes Arthur come off as a jerk for dallying with a married woman - Merlin even tells him to "cover this up" when it threatens to come out or he'll lose his crown. Gee, does this seem like the kind of guy who people would revere as "the once and future king"?
* The writing. Even the good acting from the majority of the cast can't overcome the poor writing. There are plotholes and logic failures everywhere, and more than once the plot relies on character stupidity, when in the real world it wouldn't take a genius to start asking questions and the whole thing falls apart like a house of cards. This was evident from the opening scenes of the series and continues right the way through to the end. Unfortunately for the producers and the tv network, bad writing can kill a series no matter how much money you invest in the show (and apparently that was a lot in the case of "Camelot").
In America the show received underwhelming viewing figures and has been permanently cancelled - the feeling does seem to be that the bad points outweighed the good, and given the viewing figures and the money poured into the project it wasn't making a high enough return. For me, I can definitely see the positives in the show but I did feel that the negatives, mainly the bad writing, simply brought the show down. As the show is so hit and miss with people though I'd advise catching an episode and if you really love it then think about forking out for it, rather than buying it sight unseen. I don't think I'll be adding "Camelot" to my DVD collection, but it has enough positives that it seems to me a good number of people could still enjoy it if it's their thing.