No problems from riding in the rain. If you do a lot of riding through standing water it will splash up and you'll need to re-grease your wheel bearings and shock linkage / swingarm bearings, though.
If you ride through really deep water you might want to look into how to dry out a bike after it has been totally submerged. I can't help you with that, though, as I am disavowing any knowledge of the subject.
you may want to grease your sparkplug cap, ive had my bike cut out due to water getting in there and shorting out the cap to the cyl head while running through water. i had a new plug cap at the time too!
The only issue I have with rain riding is vision. Because I'm too darn cheap to buy tear-off's, I keep a few paper towels stuffed in my pants so I can wipe the goggles. Of course, if you stay out in front, mud is never an issue.
I do use tear offs, but seldom in the rain. The water likes to get between them and the lens which makes it really hard to see straight. I can't speak for laminated tear offs though, they may be better.