Before you choose, you really need to ask yourself: do you get regular condensation in your kitchen or is that just normal? Because if you've got constant humidity (cooking steam, windows sweating), honestly neither one is ideal long-term.
With self-adhesive vinyl, yeah it goes up super fast, but how long it lasts really depends on the product quality and especially on how well you prep the wall. The corners and edges are where it'll fail you - that's where it starts peeling up. And once it starts, it's done for. After a few years you're probably gonna have annoying little bubbles and lifting.
Traditional wallpaper, okay it's more of a pain to put up, but if you do it right with decent humidity-resistant adhesive, it lasts longer and it's easier to fix just that spot without wrecking the whole thing. The key is really wall prep and good ventilation after you hang it. If you don't want too much hassle, you could also just go with a good washable paint and stick some tiles or adhesive panels over the problem areas.