Hi Sean,
The leather holds up really well in the rain - you just wipe the bag off afterwards and let it dry out in your garage. It will look just like it did before you took it out after a few hours. I have not had any problems with my Walker and it has been out a bunch of times in the rain.
A lot of people ask what happens to the bag when it gets wet - the same thing that happens to a cow - it gets wet and then it gets dry.
If it is nasty out - I tend to use my Llama which is a two pocket ballistic nylon bag with leather accents that is the same silhouette as the Walker but quite a bit less expensive ($250 with shipping). The ballistic nylon beads water off more obviously and it is a bit easier to wipe down if it gets muddy.
I totally understand what some of the guys are saying about cost, etc. An $800 golf bag is not for everyone, for some people it just doesn't make sense whether they can afford one or not - to each his own.
Just like the other guys who posted their photos, I love my Walker and Sunday bag - I would rather play older clubs and spend $800 on a leather golf bag that will last forever than spend $50 on a sunday bag and $1500 on a new set of irons and woods that will probably be replaced in a couple of seasons.
Feel free to PM or email me if you want any more info.