I tried Slip Plate/EZ Slide and was disappointed. I pressure washed it, wire brushed it (using a wire brush on an angle grinder), then brushed on 3 coats of Slip Plate/EZ Slide. I let it sit for a week to dry. The Slip Plate/EZ Slide started coming off within 2 hours of use and the grass buildup was less than before, but not a big difference. Now I spray it with WD40 (don't use the small cans, get a gallon and one of their pump sprayers and it will be much cheaper) and it works better than the Slip Plate/EZ Slide and is much cheaper and faster and a lot less work.
I agree that mowing dry grass helps a bunch, but in the spring around here there just isn't any choice sometimes or the grass will be knee high.