I'm giving this tire four stars because once the tire is mounted on your bike, it performs well.
However, I had a lot of trouble mounting the tires on my rims. What used to be a ten minute task in tube-land ended up taking me most of the day. Granted, this was my first experience with tubeless tires so it's not the tire's fault I was on a steep learning curve.
I ended up inadvertently ruining one tire by inflating it to the max and then having it explode spraying me and my bike with sealant. Again, mea culpa. I thought taking it up to the max air pressure would ensure the bead would seal. Unfortunately, the bead didn't hold for more than 15 minutes and after it popped, I was unable to re-mount the tire as it seemed like wire inside the tire had been stretched or otherwise damaged. Again, not the tires fault!
I ended up purchasing a Schwalbe tire as a replacement for the damaged one since I couldn't find another G-One Speed in stock at my LBSs. I hope this is useful to someone with a big caveat to not inflate your new tire to its max!
I got these tires because its difficult to find high performance puncture resistant 650b tubeless tires in the 1.5 (38mm) width range. I used them on the 235 mile 2 day Ride Across Wisconsin last summer and was very happy. No flats, plenty of Cush and traction and I had no trouble at all keeping speed with folks on full fledged road racing bikes.