It has a couple of favorable reviews on eHam. I've always been suspicious to the design using only 3 radials for the skirt and the cone. I use the Diamond D-130NJ. It is about twice the price of the Hustler, but is quite well built and can be ordered with an N connector.
The thing to understand is that you are trading off bandwidth for gain with any discone antenna. Also, most commercial discone antennas are hybrids. The discone portion operates from about 100MHz to 1000MHz (tops). The low frequency coverage is provided by a base loaded whip using the rest of the antenna as a ground plane. Most advertise 25-1300MHz coverage. However, they are tuned to about 50MHz (for 6 meters) and perform very poorly below. Very disappointing in CA where we have extensive low band use by the CHP. I have substituted a longer whip (48") on mine and have gotten good results with no apparent compromise.
I you don't need low band you can remove the coil and whip assembly and have a straight discone.
One of the reviews on eHam mentions that the Hustler works poorly at 476MHz and above. No good for a discone. The Diamond works well up to 512MHz (the highest I can measure). Seems to get good reception at 855. We have very few 700 MHz and above systems here.