These are really handy to have. I have the 1000 pound version from Harbor Freight. I put an MDF top on it, and use it for lifting heavy work pieces to a comfortable height, and also for getting heavy items in/out of my truck.
My only (relatively minor) complaint is that if I raise it up and leave it up, it'll leak down overnight. That's typically not a problem, though, since it only takes a few pumps to bring it back up to work height.