How much they on sale for?
They are garbage. Hated it when I bought it and tried it. Tight on the track and doesn't lift the @$$ end up. For the extra $$ get yourself one from Royal Distributors. Works great and will lift the track fully off the ground and keep your sled fairly level. Only downfall is the wheels they offer as an add on have no lock on them so I opted out of the wheels.
Has anyone tried the Sled lifts from Princess Auto ? They have them on sale this week.