I have the center kicker on the frontier I just got. Mixed review so far. It really only rakes the center maybe 18 inches, so the baler still leaves a little on the edges. In heavy stuff, it wanted to clump up a bit but that was probably because I was still figuring out what ground speed worked the best. I ted my hay and the kicker does seem to leave less on the ground. Since replacing teeth on the baler is a PITB, I don't mind leaving a little behind! I took the kicker off at one point, and the baler did leave quite a bit more. I haven't seen where it makes the window noticeably uneven. I think I contribute more to that by getting over two far and not taking a full bite.