So, they're slick for just storage. They require less prep than a normal 2-post in terms of slab depth since they're self supporting, which is nice, but you still can't do wheel and tire swaps,suspension work, etc, on them, which to my way of thinking is 75% of the reason to get a lift.
That said, they're a better, more stable storage solution than a 2-post, and the lower clearance height might make it perfect. Mike's is a 2 post setup, but he has something insane like 25 feet of ceiling height, and a super-wide lift that makes it easy to use; his garage is bigger than Paul's shop.
Also keep in mind that anything parked underneath one for a considerable amountof time is subject to all the little crap that normally comes off cars and is ignored on the pavement; brake fluid seepage, oil, tranny fluid, etc etc etc. Since most people think of it as a way to huck a project car out of the way as opposed to a perfectly maintained garage queen, it's something to think about.
If Jeff's ceiling were higher I'd be thinking about a cheap one too
