I have to interject and say that I am truly disappointed with Versace leather belts. That isn't to say that other items from them aren't higher quality, but I have two belts by Versace, one was from eBay. The leather cracked very early and became unattractive quickly. I thought that perhaps it was a fake or just a crappy model, but I bought a second belt at retail as I am very attracted to the minimalist yet flashy design, and unfortunately this belt didn't last any longer than the first.
That is my only experience with that - I am unsure of Jil Sander's leather products but my overall feelings with Sander, pre and post-Prada is a thumbs up. I've never been disappointed.