Man, it was painful, but that semi-good sort of painful, wherein I, at least, tend to smile and laugh through the pain. Along the lines of, "Man, I didn't know it could hurt like this, ha ha ha." What I did find useful, however, was that I could control how much pressure I was applying by using my arms and legs to take some of the weight off the area being rolled. There are also similar exercises that can be done with a tennis ball, to affect smaller areas, something very useful when dealing with hard-to-reach muscle groups. Considering that I haven't yet found a massage therapist who will do what I need on my glutes and hamstrings, a way to massage them on my own with my own body weight could be a very good thing.
One thing made me pause while thinking about this therapy. In massage therapy school, we always learned that deep strokes should always go towards the heart. The veins in the legs are equipped with valves to aid venous return against gravity. I was told that doing any deep massage downwards on the legs could potentially damage these tissue structures, especially if there was an underlying weakness. Since, on a roller, you're using effectively the same pressure back and forth, can this cause problems on the downstroke? Or is the force spread over a large enough area that it doesn't affect the veins? If I get a roller and start using it, should I try to limit the amount of pressure when I'm moving that way against the roller? That would certainly be the easiest way to have my cake and eat it, too.
Speaking of which, I ate some chocolate cake yesterday. It was delicious.