I actually find them to be consistantly priced with the exception of the dreamers. For 10k you can have a new sled, any brand. For 9k you can have an under 500 mile last years sled. For 8k you are into the low mile 2 year old models.
The pitfall is that they get better every year. '11 PRO's had the most issues, '12s are maybe the best chassis with the same motor. '13s get cylinder improvements but the belt drive and a-arms required to get the wieght down further can be a liability. My '13 with ~550 miles has blown both a QD belt and the drive belt. Otherwise it is AWESOME, no regrets. 14's appear even more reliable with better a-arm gluing and stronger QD belts.
'10-11 Cats are pretty good buys. They are reliable, durable, powerful and great Mtn sleds. Going back to one from my PRO though makes them feel dated. They work, just not as well as the PRO. '12 Cats were panned pretty hard. Not the best riding sled, and not light. '13's get the better 2.6 PC track and I think some steering changes. Better, not great. The '14's are a better ride, pretty close to the rest of them, '14's and a viable choice.
One of my riding buddies is on an '11 XP e-tec. Other than him repeatedly crashing it, it seems to work great for him. I don't like how the Ski-Doo rides. I did a demo ride last spring on the '14s, good sled for sure, just not as natural for me as the PRO. Everybody raves about the Doo motor, doesn't impress me any more than the other two 800's.
I did a ton of research before dropping the coin on a new(er) sled. I found a '13 PRO in Dec for $9500, with 5 miles on it and it was in my town. I know that I will probably have to put pistons in it this summer. I have 400 miles on the second QD belt, seems to be taking the abuse of lots and lots of deep snow.
I think the PRO can be the highest maintenace of the three. I also think it is the most rewarding ride. I am not a fan of either of the other two chassis. I opted to take on potential motor issues over riding a 50 lb heavier, less nimble sled. The XP or XM might feel great to you coming from the Rev. I can't fell ANY difference in the XM track and suspension sillyness, just be SURE to get the e-tec motor. Doo has the best warranty. Make sure you have a GREAT dealer if you intend on using a warranty. Otherwise it is easy to loose the best month of the season in the shop.
I would want the lowest milage, well cared for 12,13,14 PRO I could afford.