A very brief history:
The Ovation Ultra GP was built by ovation in 1984 to rival the Gibson Les Paul series. (Hence the name GP which stands for Guitar Paul).
No-one (including Ovation) knows how many Ultra GPs there are in the world as Ovation did not keep track of production numbers due to the time of flux in the guitar industry. There are probably about 300-500 in existence and they come up for sale very rarely. You cannot talk about the Ultra GP without mentioning Josh Homme, there are Ovation Ultra GP fans and then there are Josh Homme fans. I'm somewhere in the middle as I like QOTSA but it's not the reason why I went for one of these. People chasing Josh Hommes tone caused the value of these guitars to increase dramatically. Generally there is roughly one Ultra GP for sale every year so if you have your eye on one it won't stay around for long.
So what is the guitar actually like:
It's an absolute all round beauty. The playing action is great for me, it is quite a heavy guitar but then so is a Gibson Les Paul. The weight balance is great. I have a full red GP and I'm looking at getting another as a backup, they come in a red/orange sunburst, red and black colours. I have heard that the black ones are a bit rarer. The tone is just fantastic and I can see why Josh Homme held on to his when he first got his hands on one. It has a very solid construction and in my opinion (and I know this is highly subjective) I think it sounds nicer than an equivalent Gibson Les Paul. Perhaps I am biased (because I have an Ultra GP) as I have never really been into the look, feel and (now common) tone of a Gibson. The Ultra GP for me is just something slightly different all round.