I did my due-dilegence, as I'm sure you and your freind will do, and I ordered a Bend-Pak HD9 XTW (Xtra Tall and Wide). As in the first post, make sure you know what ASL certification means and that you only look at lifts that are certified. Bend-Pak are commercial lifts down-sized for hobbyists,
not some fly-by-night outfit that orders them on spec from China.
Also, the type of pump is critical and Bend-Pak is one of the companies that use the best pump. Don't be too confused by Locking mechanisms (ladders, screw-type, etc.) as a certified lift must have a good locking system. As far as add-ons go, I was told by the owner of a Bend-Pak outfit that casters rarely are needed and that if you do use them and move your lift, always re-check all legs for plumb and re-shim them. As for 110V or 220V, the difference is the speed of lift, which is about 30-40 seconds for the 220V and 1 min 30 sec for the 110V. Of course Bend-Pak only offers the 220V.
In the end you have to like what the lift offers you and each one is slightly different. Again, the keys for me where certification, commercial experience and the best pump.
Good luck!