I wasn't getting consistent results out of my forehand roller. I have been trying to improve my backhand roller but for the past months the ground been either buried under snow or far too muddy to make real use of it.
If you want a reliable sidearm roller, use a fairly stable roller. A stable roller is much easier to predict, just like a stable air shot is easier to predict. The nice thing about a sidearm roller as opposed to a backhand roller, is that you can put a sidearm down much closer to vertical than a backhand.
I've read a great deal about not using the roller, i.e. it's just not reliable enough. Then I looked at the roller video that Mark Ellis has at the Discraft site. After you watch that, you'll be amazed. The shots where he bends the forehand roller through the trees so that it goes right, hits the ground and rolls left, then fades hard right around a bend are amazing IMO.
to me rollers are unpredictable, too many variables, i throw a pretty good roller, when they work they are beautiful, but when they go bad they go really bad. my most dependable roller disc is my champion beast