It appears to me that if you use Vegas on your Linux machine then all of your TCP connections use Vegas, which will make you a second class citizen to all the Reno folk out there on the internet.
If you assume that your own uplink is the only bottleneck to be dealt with (say you are serving torrents over a DSL line) then this is reasonable, but I don't think I'd want to yield to all TCP users everywhere with all of my outgoing traffic.
There are also some scary comments in the notes from before it was rolled into the kernel, like the code doesn't handle route changes.
I can see why a vendor would choose something over which they have control.
I don't think the article documents any details. Maybe I missed a link.