Oh, it is. I have logged about 18,000 miles on three of these (well, two were the earlier version) over the last five years.
The XRF5w is definitely nice and, I agree, quieter. I assume it makes for a very efficient transmission. But there's something special about the XRF8, because its closely spaced gears allow you to restrict your pedaling cadence to a very narrow range, which makes for more efficient pedaling. I like them both.
The middle 6 are closely and evenly spaced, but there is a big jump from 1st to 2nd, and from 7th to 8th.