I have a pair I picked up last winter. I’ve used them about a dozen times so far, so only limited experience. Overall I like these wheels. My purely subjective opinion is that they seem pretty fast, but I don’t have any real data yet. They do have a couple of compromises, in that the braking track is very narrow so you need to have your pads carefully adjusted, and they are also not the stiffest wheels in the world, in that I notice some flex when I’m climbing out of the saddle. But wheel stiffness is not really a big deal for me, I’m not a big sprinter type. There is also a bit of sensitivity to crosswinds, nothing like H3s, a bit less than Zipp 404s, but still noticeable.
I bought them new from a private party for a lot less than retail. I know that last fall there were some retailers selling them for less than list, shop around. Personally, I think $850 is too much to pay for aluminum rimmed-wheels, but Ksyriums go for more and the Vigors seem a little bit faster to me than my Ks.
I’m not sure it is valid to compare the Vigors to a wheelset that costs twice as much, I’m sure that overall the Zipp is a better wheel, in terms of performance the Zipp has a deeper (44 vs 34mm) and more aero rim but more spokes (44 vs 30), so performance-wise you probably won’t see a big difference.
The Zipp 303 I would expect to be much more aero due to a better rim shape, dimpling on the rims (for what its worth) and a deeper rim. The number of spokes is not as important to drag as the shape and depth of the rim. The Rolf wheels will be better than a shallow section rim, but I had a pair of Elan and my teammate had the Vigors and we swapped quite a few times to compare wheels. I found the breaking to be poor for aluminum rims with significant brake judder and the rims were quite flexy as well, even under my skinny 140lb frame. I save up for the Zipp’s or look for a used set. You might also consider a set of Jet 60’s as well.
Personally I would go for a 404 set, ahead of the 303. If you are worried about crosswinds I would go 404 rear and 303 front. I have no problem with fast descents and crosswinds on my road bike with a set of 404’s.