Glad to hear this because I really like the look of lambskin better than caviar and have not seemed to have the issues that everyone kept talking about!No issues for me either. I think it's just a common sense thing which is not particular to lambskin. My grey is not so light it would particularly show up anyway. Dark colour will transfer to any bag - be it caviar, patent, lamb or fabric (and any others i missed!) if you are not sensible with it. No dark jeans with light colours (whatever they are made of!) and you'll be fine.
The leather however on the lamb jumbo is very soft so it doesn't hold the shape as well as some of my other bags.
I wouldn't recommend putting any coating on a bag - it will hold up fine. And lamb is a lot less delicate than all the panic stories on here!