I'll toss in my $0.02 in favor of 4 post lifts:
1. 2 post lifts may be great for quick service because they give the greatest access to the underside of the vehicle, but are lousy for storage as they leave the suspension fully extended, and lousy if you need to work on a suspension bit when it is compressed - like restoration work;
2. 2 post lifts require more height of your garage ceiling;
3. 2 post lifts require a solid foundation to properly and safely mount the posts;
4. 2 post lifts can not utilize drip trays to keep drips off the car underneath the one on the lift if being stored;
5. 2 post lifts & their load are less stable than 4 post lifts, certainly if the load is not positioned properly or you are rocking a rusted on part, and most times the garage floor does not have the proper foundation, concrete type or mass of concrete to support this type of load;
6. 4 post lifts are more versatile by far, have none of the negative issues of #1 through #5. They can be installed in a low ceiling garage on a standard garage floor, great for Little British Car work. I have a 9' cieling and can store two Stags in one spot. You can work on any part under the car with no interference with the support ramps, open and close doors, jack independant wheels for work, lift only the back, or the front, and still use it for engine removal, etc. Many suppliers include the jacking tray, ramps, drip trays AND castors to move the lift around WITH the car on it. I can also use the ramps to chain up the suspension for anchoring places that need to stay in one spot when I work and jack up another spot. I could use a second jack tray, but with some lengths of 2" I-beam and the problem is solved. On Independant Rear Suspension, I can remove the differential while still leaving and changing the load on the supension, changes suspension bushings and tighten the suspension with the full car load on the components as required, something that a 2 post lift can not do without extra high lift jacking stands that cost $200-$300 each. These stands put a 2 post lift load in an unstable position. Using the jacking tray and drip trays on a 4 post lift, I can do oil changs in a snap, 2 post needs a long neck funnel and tank, another $300 accessory.
After a long search and evaluation, I bought a four post lift with all the accessories included in the base price, never looked back.