I have a log arch I bought from Northern, its not the best one out there by far, the box was destroyed when it arrived, & it was missing parts, with winch gear stripped the first time, etc. Its too short to be able to back up in the woods, the winch web jams on the roller, & the chain they give you is a joke. However, all that being said, for the price (sub 250 on sale) it works surprisingly well (with a few upgrades). I tow it with my Polaris 700, & have moved long logs with ease. The arch is short so the tail end typically drags, which helps on downhills, but mine are typically short hills. My Polaris is rated to 1050 pounds from the factory, but have towed a 1500+ popup camper with it no problem, and even heavier logs with the arch. I have lost traction up hills, where I had to leave the log & go get the loader to get it. But you said you were all downhill. I don't know that you are pulling 2500#'s with an ATV, but the arch definitely helps lower the rolling resistance.
I figure you spend +/-$75 in gas to round trip the skidsteer, so if you factor in the lost 5 hours of extra travel, this thing isn't a terrible investment.