My wife has a 2000 ZR 600 EFI with 3200 miles. Doing the trails at 45 to 55 mph, she gets around 8-9 mpg. She gets worse if she's doing under 30 mph. Each sled has its own powerband and optimal rpm for cruising. ZR's are designed to go fast (race sled heritage) and they won't get the best milage. But they are also not the worst.
My 2006 Crossfire 7 gets around the 11-12 mpg doing the same speeds (should do a little better but I'm not a lightweight individual).
Pushing powder or breaking trail will lower milage a lot, especially on short tracks like the ZR's in deep snow (don't float on top as much as longer tracks).
ZR's are also a little heavy on oil consumption, but I'd rather spend an extra $50 a year on a couple of extra jugs than do a rebuild on the engine.
She loves her ZR because the short track feels light and is easy for her to toss around in the snow. It handles any ditch banging she throws at it and handles well on trails. Overall, great sleds.
The ZR 800's were actually better on fuel than the 600's because they don't work as hard to move the sled. But with the 800's, you better wear a seatbelt to hold you on it.
Good luck. Just my 2cents.
