I use ramps PLUS jack stands, and, if the tires have to be off, I do one side at a time, and the tire also goes underneath.
WHen I was young, I used to just use the scissor jack to lift the car up. Got under the car with just that all the time. One day, got under there and couldn't break a fastener free. Climbed back out, went to get a tool and the scissor stand had folded right in half and front disc was on the driveway........
Scared the living BEEP out of me. THank goodness I wasn't under there. Pure luck it wasn't.
Never again. Now, I go WAAAAY overboard if I'm getting under vehicle.
These jackstands in post seem like a good deal, but I would use them in conjunction with other measures, not by themselves.
EDIT: For ramps, I toss them every 5 years. Just peace of mind for me. I'm talking about non metal ones of course.