The real difference isn't just vinyl vs wallpaper, it's mostly about the state of your walls. In a kitchen in Liège with the humidity, your worst enemy won't ever be the adhesive - it'll be the humidity fluctuations that make any kind of covering swell up. Self-adhesive vinyl holds up better than regular wallpaper in that regard, true, but you really need to check that you don't have infiltration issues or chronic condensation before putting anything up. If your walls are already damp or you've got mold spots, even the best vinyl will peel off or warp within a year.
For self-adhesive vinyl specifically, durability really depends on quality and how you apply it. Cheap stuff is pretty much guaranteed to bubble and peel at the corners after 6-12 months, especially near the sink or above the stove. But decent brands are more solid - I've seen them last 4-5 years without a problem. You do have to smooth it out properly though, working from the center toward the edges to get the air out, and anywhere there's movement (corners, window edges), that's more at risk.
Honestly, if you don't want to deal with the headache, a good textured finish or special moisture-resistant paint is more reliable in a kitchen than any self-adhesive covering. But if you really want vinyl, pick a good one, prep your walls perfectly (dry, smooth, clean) and avoid areas with heavy air currents.