There are several differences between Victorinox and Wenger.
-Wenger's can-openers are like the ones on Camillus boyscout knives, the kind that look like a hook, and don't have the small screwdriver that you can find on Vic's can-openers.
-Wenger's screwdrivers lock when pressure is applied, this is a sweet feature!
-Wenger offer's locking blades on standard size (85mm) knives.
-Victorinox standard sizes are 111mm and 91mm (there are also 58mm, 84mm, 108mm, 74mm), while Wenger's standard sizes are 85mm and 120mm (they also have others).
-The blade on Wengers is different from the one on Victorinox SAKs, it has more belly and is a hair thinner. I like it very much.
-The scissors on Wenger SAKs have self sharpening serrations and a more solid spring than Victorinox scissors. Even die hard V'nox fans sometimes admit that Wenger's scissors are better.
I could go on for ever, since there are lots of little differences. There I've heard that Wenger backsprings are weaker than Victorinox backsprings and have read about some failures, but none of the 10+ Wengers I own and use ever showed a problem.
For all your SAK needs, check out
www.sosakonline.com there are a couple of Wenger VS Victorinox articles you might find interesting.