What do you want to do with it?
I have a scissor lift, you need ramps on either side, or recess it into the floor to drive low cars over it.
It obviously has its limitations, but its still so much nicer/quicker than lifting a car with a jack and axle stands. Lifts the car over a metre off the ground quickly and easily. A nice height to sit on a stool to work on breaks/suspension, also good for body work, engine pulls etc. Exhaust/brake/fuel lines/gearbox are fiddly above the lift, but you can just lift the car up, then lower it onto tall axle stands, or wheels stands, then lie the lift flat.
Whilst it is "portable" you will not be zooming it about the place!
I would like a flush mount twin scissor lift like Keyser listed, but money and roof height are slight inconveniences at the moment.