I was considering a 4 post lift as I thought that they were freestanding and could be put on any conventional garage floor. I didn't expect to have to change the garage design or get a permit (better check). I just need the additional ceiling height. I think that the 4 post units are great for storage but the 2 post units are better for working on the car as the wheels can be pulled easily. The scissor lifts don't appear to allow for storing a second vehicle underneath and many of them are of an "in floor" design which seems more costly.
Unfortunately, by the time I get the lift I will be through restoring cars (famous last words). Besides, I'm getting too old to crawl around on the cement floor.