I do very little leather due to most i go to look at require more than a clean, infact most of the time when they mention leather on the phone i just tell them to ring Steve Gunn now (untill i get some extra training).
So in my limited experience ive found the magic sponge thingy mabobs good, i like them.
Products ive used are Extracta, LTT, Buffalo and furniture clinic and ive managed to narrow it down to errm.....LTT, Buffalo and furniture clinic
I would edge slightly toward Furniture Clinic but like i say i havnt gave them all a fair crack of the whip.