I've owned my R8 Roll Recovery for around 4 months now. I'll list some of the pros and cons...
Pros:
-Extremely good for calf muscles, hamstrings, quads, abductors, tibialis, achilles, and IT band stretching.
-Very easy to trigger specific points on your body. (For example my outer calf is always very sore, and my R8 can hit the spot perfectly.)
-Very portable and lightweight (brought it through security at Ohare airport last week with no issues).
-You control the pressure. I hate putting a lot of pressure on my achilles, but with the R8, I can gently roll it across my muscles without any discomfort.
Cons:
-It is expensive, but I do think it is worth the extra money.
-It can be a little tedious to use at first, but you get the hang of it pretty quick.