There are a lot of members who use and swear by that product. I've never used it but love Hydrophane instead. If you are concerned about having your saddle darken, then try Blackrock. I use Blackrock on everything leather including my wife's rather costly handbags.
Passier Lederbalsam is a conditioner. It works really well and I use it on my old/stiff tack to soften it without oiling it. Doesn't darken leather colour - it will make it a richer colour though, so it reflects light better.
To clean tack, I use Fiebing's Saddle Soap. If you use it every day after use, it generally negates the need for conditioning.
Doesn't darken leather colour - it will make it a richer colour though, so it reflects light better.
I used it today on my saddle and this is exactly what happened. For about the first hour or so it stayed dark (really dark), but I'm lucky it came back down. The color is much richer though. Like you said it would be.