We own a 2007 ultra 250x. These ski's hold 20.6 gallons. If we ride hard we can burn that 20.6 gallons in 2-3 hours. As a matter of fact according to the owners manual, at WOT I believe you can get 69miles out of a tank. All depends how you ride it though.
They handle like they are on rails to. We bought ours new which was right at 13,500 out the door I believe. We have close to 100 hours on it I believe. Only problems we have encountered is the plugs. It loves premium. If we try to run the cheap stuff it fouls them out everytime and runs like crap. Overall we love it to death. It's a very fast ski that handles like a dream. I have been caught in a storm twice at the lake. Having waves about 6ft tall and it took it like it was nothing. Also got caught with 3 people before and although we slowed down to about 15mph we made it through. What was hurting us was that we had to go against the waves to get to the boat ramp.
40 hours on it doesn't seem bad at all. I know 100 hours is still low for an 07. I'd say that's not a bad price in my opinion.