I don't have an XS, but I do have a Wings, and it should be pretty obvious that you'll get more overall utility from the XS.
For what it is, the Wings is a neat little knife, and I'd say that it's probably a little better for harder cutting tasks than the XS would be, but it's a lot bulkier, and the fit and finish aren't even close to what you get from a Vic.
I don't have a lot of problem with the opposite thumb hole on the Wings, but then I've never used it for a long period of time either.
Ever since I got the Wings I've struggled to find a regular home/use for it. If I were faced with this decision I'd get the Vic instead.