I use various products depending on what condition the leather is in, for a quick clean I really like Effax leather combi, it's quick, easy and leaves leather non greasy but well cleaned and conditioned.
For drier leather I like Effax Leather Balsam, Ko cho Line and Jeffries leather care.
Grand Prix leater gloss, I do alot of showing and it makes my tack beautiful, soft, supple and shiny.
I have regenerated quite a few saddles with this also its amazing :O)
Also 1 small tub lasts ages I clean all my leatherwork at least once a week and i have 3 horses had my tub for 3 yrs so far.
Teresa
Also, i have a traditional glyserine soap, one of which is Carr & Day & Martin, which i somtimes use with a bit of milk(!) on the sponge. My horse's owner also has a random one in a round pot.
When tack is really muddy/sweaty too, i use the c&d&m cleaner in the spray.
Use it on my riding boots too, and on my riding hat strap!