My experience has been positive. Got pulled over when I had a tail light out. When the officer got to the window I immediately said "before you go any further I need to tell you I have a CCW and am carrying". Officer said thanks and told me my tail light was out. Had me get out of the car (pistol was in the console between me and passenger seat) but other then that no problems.
Afterwards he said something to the effect of "I love people with CCW because before we pull them over we know they have gone through the steps to be legal and therefor are probably the good guys"
One other time years before that when I got pulled over and wasn't carrying a different officer said "why bother getting a permit if you aren't carrying"
In Ada County CCW training the Sherrif's Deputy giving the course pretty much flat out said "Please carry your weapon. Chances are you will never use it, but chances are if you have to the police aren't going to be there in time to do it for you."