Hi Sebastian - I updated your thread title to include a little more context.
Personally, I highly recommend Leatherique products - they're second to none and can really make leather look new again. Not only are they great for a complete rejuvenation, but they're also wonderful for maintenance as well.
I've tried almost everything - Lexol (terrible), the Lexus branded products, Meguiars, Armor All, etc. Leatherique is a game changer.
I had a GS with ~115k on it, and the leather still looked new because of Leatherique.