Back in the day we used to test these cars by how much they bounced when we dropped one end - a suspension test if you will. Matchbox cars had softer suspensions, but Hotwheels lasted longer.
I just bought some of these for my Nephew's son and it seems like Hotwheels don't have normal cars anymore. I got him two of each, but for old time's sake I had to go with Hotwheels.