So I finally got around to seeing this one. (
http://www.imdb.com/title/tt0045966/)
Interesting film.
It's very dated, of course. By today's standards, the acting is cheesy, and the combat choreography is atrocious (bordering on comical), and the editing is a little odd at times.
However, the film does try to adhere (mostly) to the Arthurian legends, and makes a point of exemplifying the chivalric aspects of those stories. One of the writing choices they made was to have Lancelot and Guinevere's infidelity be in heart and appearance only, and not actually acted upon (unlike what Excalibur portrayed, of course). They also portrayed Merlin as more of an adviser, and not a wizard. There's no magic, with the only thing getting close is Excalibur stuck in the anvil (not a stone).
In terms of the occasional accidentally comedic moments, one of the ones that really struck my funny bone is a moment in one of the battle scenes where one of the warriors on horseback strikes an enemy, knocking him from his horse. He turns back towards the camera, and the scene stays focused on him for quite some time with a huge grin on his face... as if it was a huge moment of "I got him! Look, I got him! All by myself!"
The garb and armor were actually pretty good for a film of this era, I think. They set the style in the mid-14th century, so it's a combination of early plate and mail, with highly colorful heraldry.
In any case, if you enjoy older films, it's still an enjoyable take on the Arthurian stories. You just have to survive the more cheesy aspects.