I use a Mercedes jack to lift the car and then lower it on a jack stand. I've been thinking about getting a floor jack but I can't figure something out...if I use the floor jack to lift the car using the rubber bumper, where do you put the jack stand.

As for the jack failure, I wonder if one side of the car is on a jack stand and you try to lift the other side with the M-B jack, would it exceed the weight the jack can handle?

BTW, whenever I jack up the car I apply the parking brake and also put chocks in front and back of the off corner wheel.

I think the safest way to get under a car is to put it on ramps. Next safest would be on jackstands with the wheels chocked.

I once saw something on TV where a dead man was shown under a car that had fallen off a bumper jack. It wasn't a pretty sight.