we have a great relationship with a contract shop across the street from us. we've printed jobs for them when they are in a pinch and i send anything i have with more colors than i can handle over to them. we share tips, check out each others shops, etc. there are some things that we compete on, but would never go after each other. at least it seems that way for now, haha.
on the other hand, there is another shop down the street from us... i cant tell you how many times ive had a customer come in looking for a quote telling me that the guy from "the other shop" was bad mouthing us, telling them we are too expensive, yada yada. ive never even met the guy either!! i dont see how that is a good business practice at all. i look at it as a karma thing. sooner or later it will catch up, for the better or worse.