I'm going to be buying a lawn mower before summer. I have about 3 acres to mow. The main problem is hills. The back yard used to be a "pasture" and has a shallow terrace, but the big problem is the slope down to the pond. It is STEEP. Currently the guy we pay to mow uses a stand behind to do it, and doesn't really like it even with that. I'm planning on buying a lawn tractor; from what I've read in these forums I don't think I would trust a ZTR on some of my slopes. I'm thinking about getting a 1-2 year old Deere X485 or X585. Does the 4 wheel drive's extra traction on hills justify the extra cost (and I assume upkeep)? I assume the safe way to tackle steep hills with a tractor is straight up & down, and that the 4 wheel drive would help with this, but it looks like they go for at least $2000-2500 more than the 485, and I may be going overboard with this.