My opinion is discs are all pretty similar, some small variation with hubs, flat v. lenticular v. hybrid cross section, but I suspect the differences are pretty minor. Everyone thinks that more expensive = faster, but putting a $100 cover on a standard wheel is as fast as a “disc” ( http://www.wheelbuilder.com/aerodisc-data.html). So basically I suspect the speed difference with a $2,500 Zipp is next to nothing. I personally use a home made disc cover on an 808 and have posted sub 5 in my last two IM races. The biggest concern I would have in buying a lesser know brand such as GZ is the resale value.
I remember reading a lot of scathing reviews about them, particularly resulting from their rear hub and the spring-loading, zero dead point thing they were plugging at the time. Issues with the rear hub were causing chain suck and related problems when coasting. Beyond that, not sure. Haven’t tried them myself. They may have changed the hubs since then anyway.
Recent experience: bought a Boyd front wheel, great service and rapid delivery to Melbourne (about 1w), its a nice wheel with a great finish and ride, and was reasonably cheap (about $830 delivered). Whacked a home-made disc cover on the rear and had a great race setup for <$900, with no need to dick around with the rear brake. If you’re in Melbourne, I’d be keen to try making another disc cover, if you covered the materials costs I’d do the construction just for fun.
I will be looking at the wheel covers though to put on top of my 808 FC
Those articles are the reason that I thought I would come and post here OZ, I know someone riding on some shallow gravity zero rims but a friend is looking at buying them and I find them interesting for the price.
How much are the costs for a disc cover? because I am in melbourne and I am interested! haha