After working in the auto repair industry for 50 years, here is my 2 cents on lifts. I have used them all extensively and while both 2 & 4 post versions do have pros and cons, I chose a Challenger 10K Versametric 2 post for my new shop and here's why. The 4 post really only has one advantage and that is ease of placing a vehicle on the lift. The 4 post is more expensive, once you buy jacks to lift the front and rear end. It takes up more room and that means more steps to walk around the vehicle. A 2 post offers more access to the parts of the vehicle that you work on the most, front, rear, tires, brakes, and suspension. As for safety, proper placement is a concern on any lift, however I have not had a vehicle fall or even a scare. I lift my Ram 2500 crew cab long box for oil changes and tire work without fear. If I were removing a heavy part, like engine, trans, or rear end, I would use a safety stand for stability. As for additional time to set up for an oil change, if you follow oem recommendations for tire rotations, you will need to rotate tires at every or every other oil change and rotating tires on a 4 post is more work than on the 2 post, even if you have rolling air/hydraulic jacks, and will negate the extra set up time for the 2 post. Other than oil changes, everything you do on a 4 post hoist is harder than on a 2 post hoist due to the hoist limiting access.