I have one from AWK antennas, it is a 6 band version covering 6m - 20m. I've had it close to a year now and it works well. The downside to a cobweb antenna is that they are more susceptible to SWR changes when wet versus other types of antennas.
I have found that the 6m and 10m portions are a bit narrow banded. Mine is good from the lower end of 10m up to 28.500 and the 6m portion is good in the lower CW and SSB portion. But you can tune them for the portions of each band you work most.
I have 13166 QSO's with 11087 of them confirmed and 208 countries worked. Most of that has been with the cobweb antenna.