No I don't have lift yet. The cost overruns on concrete killed that this year. That being said I can say that they most useful lift for vette maintenence is a two post lift instead of a four post. I have used my friend's two post for about two years now. At first I was leery because I thought it would fall over well it did not happen of course. The two post gives you total access to the entire drivetrain and wheels from underneath. The four post get in the way of access to the central drivetrain due to the cross bars. You also have to get a second dary jack to lift the wheels off the ramps if ytou wish to work on the wheels. It is easier to drive on and store a second car but I think for actual maintenance the two post lift works best. You need at least four inches of concrete (5 or 6 would be better) so check the instructions from the lift maker and the thickness of your garage floor.
I installed my LG headers and have had then off three times since the initial installation. I have also worked on wheels, brakes, front end underneath access. Two post has the negative of have the posts being opposite of your door so it could be a little harder to get in and out. The solution is to have a long enough bay so you don't pull all the way into the lift space.
A sissors lift usually uses a hydraulic piston(s) that presses a platform off the floor . It only sits on top of the concrete surface so the quality of the concrete is not as critical since it is usually not penetrated by bolt although you can to permanently locate it. It has some of the same issues as a four post in that the central part of hte car is not easy to get to to service due to the nature of the scissors design. They tend to be a little cheaper and don't elevate a car as high.
We put a 2 post lift in and can say I don't know what we would have done without it. Everything from cleaning the bottom of the car to changing engines. We had to change trans at the Glen which is 1.5 hrs away so we brought the car home to do it.