I have only tried one, and it was relatively inexpensive, Upton Tea Imports' ZG68: Organic Green Lu'An Melon Seed. It wasn't the best green tea I tried but I enjoyed it a lot, and I also enjoyed the way I felt after drinking it, which is something that is important to me.
I have no idea how it compares to others in quality. My experience is that Upton has a few gems in the low-end Chinese green teas, but tends to lag behind on the high-end ones. I suspect there is much better stuff out there, but I also suspect that, like most of Upton's teas, that might be among the better ones in its price range.