I have the leather FXRG suit, helmet , gloves and boots.
the suit is water proof. the boots are water proof, as are the gloves.
I have no experience with the FXRG nylon version.
The only negative with the leather suit is that the leather will soak up some water- which makes the suit weigh more.
The water proof barrier is the liner- so you are wearing a rain suit with your leather suit over that.
It does work, it is warm and it makes an excellent cold weather riding suit-
I have recently begun wearing the Transit suit from Aerostich. It too is water proof- jacket and pants zip together with a back panel, but it is NOT as warm as the FXRG suit- but as the fit it to your body measurements, it does fit much better. I have long arms, so to buy the FXRG suit that fit my arms, I get a jacket that is a bit to loose around the chest and waste- but that allows for layering I guess.
It is about 1/3 the price, certainly more than half the price of the Transit suit.
my 2 cents.