I wear my suede boots in the rain a lot, but I am having a bit of a suede experiment (as in, how long can I keep it looking good). I am trying to respray every couple of weeks and brush with a suede brush. They still look like new after a month of daily wear, will be interesting to see how thy hold up.
Oh, and I think thick soles help - if they are thin soles they will constantly have water at the sole/upper seam, and will stain quicker, IME.
I love suede, so it's worth the extra care for me.