I'm with Guy, buy and then sell - but also look at Gumtree , there are a few for sale , however not much less than a new one
Engine stand, no problem with second hand but with hydraulics? Unless you know the history I'd buy new and let the next owner worry about it. And the first lift with any hoist - it's a static test, away from anything you value! Leave it under load for a while and never get your feet/legs under the load, especially when you're on the release valve! And when you dropping the valuable stuff onto the deck make sure there's nothing on the floor to puncture/crack the sump...
Oh, and check the state of the floor to make sure that you can pull the loaded hoist back or push the rolling chassis out from under.
Guy