IMHO, if the price diff is only in the 400-500 range, the Koyker should seriously be considered over the zl20. Especially if you have other plans for the tractor hydraulics, down the road. Adding power beyond to the zl20 would eat up the savings. The zl20 is a fine basic fel and have been happy with it and have had no issues so far. While trying to buy spare parts for zl20, found most were easily obtainable, except couldn't get cylinder rebuild kits. Could get complete cylinders, though. Everybody has their own price threasholds.