I can't speak for how these knives are made today, but from experience with older versions of both, I would pick Victorinox.
The main reason is as follows.....Victorinox knives have metal supports that run from end to end, making the knife stronger. If you were to open all of the blades at the same time you would see all of these metal separators that space out the blades. The spacers come up to the very edge of the knife or at least very close. With the older Wengers (maybe today's production too, but I don't know for sure), there were no supports running end to end. When the knife was fully open, you could just about squeeze the plastic scales together and make them bend inward quite easily.
Granted, I understand that you will never have all of the blades open at the same time and hope to use the knife, but i mention this for the sake of speaking to the Victorinox' better structural rigidity. The above may have changed over the years, but about 30 years ago when I bought my last Victorinox, it was a much stronger built knife than the Wenger. That knife is still going strong although it does have some tarnished/pitted metal on the separators (all blades are still clean chrome looking). It was an EDC for about 10 years (still carried today, but less frequently), and used every day during that time. With all of the abuse it's gone through, I've only had to sharpen the two main blades maybe two or three times. They just hold a remarkably sharp edge for a remarkably long time. I also like the way the scissors cut and felt in the hand compared to the Wenger. I would have to say that the blades have held their edge better thaqn any knife I've had over the past 30 years, and I've had quite a few!!!