I’ve got a HED Jet+ Disc and it’s similar to the Flo construction as in a regular aluminum wheel with a non structural carbon fairing. HED was one of the first ones to do this and has been around a lot longer than FLO has.
Both are good but I believe the HED is a bit lighter than a FLO (in the past they have been but can’t say for sure now).
It sadly doesn’t do the whomp sound. I’m tempted at times to just fill the cavity with a can or two of spray foam to make it “solid” to get that whomp whomp sound.
Aero disk covers get you to within 1% or better aero performance compared to a dedicated disc wheel for a fraction of the cost. But can be a pita to deal with if you swap it in/out frequently. I’ve seen people who made their own disc wheel by using a cheap rear wheel and cutting/gluing to their own disc over and then filled it with spray foam to get the whomp sound. I’ve thought about doing that for fun too actually since I spent a period learning to wheel build…still might do it for fun because I’m getting board not having a diy projects currently.
Another one to consider is. Renn 555 disc as it is full structural carbon I believe at a fraction of the cost of a zipp disc. It isn’t lenticular shaped and is flat. But the speed difference isn’t very much and for some frames this shaped disc actually tests faster in a wind tunnel. I think the speedy concept might be one of them (you’d have to do some poking around Slowtwitch to confirm as I don’t recall exactly and can’t quickly find it).
I did find an older thread on here for budget disc wheels…check it out.