VDC. Gives some excellent advice on AWD foibles. Let me add a few thoughts as Our family and neighbors have lots of experience driving AWD cars in deep mud, snow and ice.
First, the Legacy and the Outback are outstanding road cars, but even with the outback’s added ground clearance, as with all independently sprung cars, it disappears quickly each time you load it up or even hit a bump. The overhangs on all subaru’s, excluding the Forester are really poor. The Forester has some how with it’s shorter wheel base and slightly different valance design, managed to be a little more acceptable. If you do much heavy snow mud travel, choose the Forrester then the Ouback. The Impreza, legacy will be the absolute worse in deep snow. Con sider them only in conditions you would take an ordinary fwd car. The Rav which has outstandingly better approach and departure angles can a deep snow/mud road animal with the right tires. The CRV is good too, but the drive train provides the least consistant traction.
If you routinely rotate from winter to summer tires, that takes care of ALL rotation requirements, so find a used one where the driver actually used winter tires. All the awd cars can be significantly different in other ways. The CRV does not have a center differential per se and runs on the slip and grip with a rear clutch pack. My daughter paid little or no attention to tires, sometimes replacing them just one or two at a tire. It made no difference in 250 k miles when it rusted out. My RAV manual says Same axle replacement is fine. Differences of up to 2/32 inch is fine on the tires and using a tire gauge to measure tread depth and pressure gauge on similar tires is more important then arbitrarily rotating them.
Heavy loading and attention to tire pressure are in my opinion, as important. I would make sure I knew that history first.
In summary, CRVs are the most bullet proof, followed by the Rav. The Subarus have the best overall traction, but need only slightly, more attention. It must be noted,that the new CRV for 13 is reputed to be more full time…with probably a less reliable system. IMO, if I were to buy used awd, it would be a CRV.
The last thing I would say is…always use snow tires with awd and never buy one from a previous owner who did regular snow travel without them. The extra single wheel spinning with poor tires wears an awd system too. Great tire traction is need more in awd cars with the false sense of security they give you in being able to accelerate so well with almost any tire.
Oh, any teenage drivers who got to use them a lot? Run, don’t walk away from any deal. As with most awd systems, mud and snow yes, rock crawling, no.