Hi Dean, I actually have _both_ of the popular dog ramps, so I can tell you the pros/cons of each. I first bought the "Petstep" when at about 8 1/2 years of age, Crombie (who weighed about 105-110) began to have trouble leaping into the back of my Landcruiser on occassion (the tailgate is 31" high). He was always a proud guy, and would not accept help with his rear end being lifted (if I even could!). I chose the petstep because it was lighter weight, and it folds in half, thus taking up less space in the car. It is made out of a molded plastic, so it can get wet without damage. About a year later, when Crombie was diagnosed w/cancer, and had a 'paraneoplastic syndrome' which caused his rear to weaken, I found he had trouble making it up the petstep. My friends had in the meantime purchased the "Dogramp", and no longer needed it since they had also ended up buying a VW Vanagon for the dogs. I bought the Dogramp from them, and Crombie was able to use it until his death 7 months later. The Dogramp is a bit wider (not important to me), is longer, thus less steep, and is carpeted (my husband did end up gluing carpet to the Petstep). It is 'telescoping, so is pretty easy to use. I now have an old Rescue Berner who uses the Dogramp to get in/out of my car at the street in front of the house, and I use the Petstep to let the other dogs out of the car in the garage. I have heard that they've redesigned the Dogramp and it now weighs less and is less bulky. If I only had one ramp, I would probably go with the Dogramp. Both are available on-line: www.petstep.com and www.dogramp.com
More info than you probably needed! Jennifer Zaayer and crew in Cardiff by-the-Sea, CA