I have a 9000 lb extra tall/wide BendPak, plus jack tray and casters. Being able to use it for vehicle storage was probably the least important aspect of it to me, and in fact I have so far not done that even one time. I planned it as part of an expansion project for my workshop specifically to add a lift that involved adding on to the building (new foundation) so I was in a position to have whatever foundation poured that I needed. In fact, the foundation I had built is capable of supporting either two or four post lifts. At the time I made my final decision to go with a 4 post lift, the aspects that were the deciding factors for me were the ability to put it on casters and make it semi-movable (it's not as easy to do as they make it look) and safety. If you get a heavy vehicle up in the air and then subsequently remove a heavy assembly from it, like for example the front subframe and engine cradle (with engine), on a two post lift it can change the balance enough for it to tip and fall unless you have the vehicle supported at the ends with stand jacks. (I also bought a set of 4 such stand jacks that I use even with my 4-post for some operations, such as picking up my tractor with my shredder mower hanging off the back so that I can work on the underneath side of the shredder.) The only jobs I've found that would be easier with a 2-post so far are those on and around the wheels and "outer" suspension components. They aren't "bad" at all with my 4-post and definitely tons better than trying to do them with the car on the ground and on jack stands, but I can tell they'd be easier with a 2-post.
If it helps, now that I've had my lift for over a year I'm positive that I made the right choice. I use the snot out of it and it makes what would otherwise be unpleasant jobs such as replacing front and rear wheel hub/bearing assemblies on my wife's 2010 CTS much less of a pain - almost enjoyable.
Here are links to the lift I have plus the accessories/add-ons I have.
Out of all the accessories, the only one that I would "undo" is the Air/Electric utility station. I had to fabricate additional mounts for it because the mounting brackets supplied with it were way too flimsy, and the unit itself was little more than a duplex electrical box, air regulator, air lubricator, plus a few fittings and some wiring. I could have fabricated one myself using individual components for a lot less money that would have been just as good if not better.
I also considered getting one of the rolling air/hydraulic scissor jacks for doing suspension work instead of using the jack platform and the two bottle jacks, but decided not to because of cost and weight - those things are over 300 pounds and if I ever needed to move it completely out of the way to get to the whole underside of a vehicle, that would have been a pain, plus I don't need to lift the wheels of a vehicle often enough to justify having one when I can do the same jobs with the jack platform and a couple of bottle jacks, or use a pair of the tall rotary lift jack stands.
So far, the only times I've used the casters have been when I first got them to try them out to make sure they work, and to 'demonstrate' them whenever I'm showing my workshop to visitors.
Also FYI, my lift does require 240v service.