It is really amazing that the books have been written in the mid-nineties, but so few people do know them! I myself discovered them last year.
And they are really good. Cornwells Arthur is the best saga I ever read, in both historical and fantasy cathegories, it is much deeper than Uthred saga (which scores anyway a second or at least third place in my own ladder).
Cornwell is the main reason I love Brytenwalda so much, it recreates a very close atmosphere with the books, allowing you to revive them, even though you have already read all of them (good, Uthred saga has not been completed yet, but I can'T presently read anything new until Cornwell does not publish the next :-p )