I've a 9K Challenger asymmetric that I use exclusively for working on stuff and a 10K Bendpac 4 post. The 4 post is storage most of the time, but there've been a few times when I've worked on a car with it. I'm very happy with both of them. Both are well built and stable with a car or truck up in the air.
Working on a car on the 4 post is much more challenging than the 2 post. You're always bending to get under the ramps or cross over beams. Can't tell you how many times I've hit my head. Removing/installing wheels/tires is easier and quicker with the 2 post. Bleeding and adjusting drum brakes is also much easier on the 2 post.
Last summer I was sorting out a gasser with an 8 3/4 under it. Redoing shocks, mounts, leaf springs, etc I had the rear end in and out of the car at least 4 times. Kept thinking how much more difficult that would have been with the 4 post.
I don't like putting a convertible up in the air on the 2 post. I'd done brakes in a C body convertible before getting the 4 post and was shocked by the amount of body flex it exhibited while going up, even with the arms as far forward and backward as I could physically get them. I went and got some tall jack stands and supported the rear end and the front lower control arms with them before I was comfortable leaving the car up in the air for the couple days it took me to complete the job. I wouldn't even attempt it on a rusty convertible.
I've also got a b body convertible and will be putting frame connectors in. Definitely a job for the 4 post lift.
Go with 220V motors. You'll be happy with the speed going up.
