Thank you reviewers and thank you yelp!  Our AC unit stopped blowing cold air, even though it was running.  After reading the reviews, I called Black Mountain Air and spoke with Todd.  He was able to come over the same day and quickly diagnosed a problem with the control board.  An hour later, the AC was running smoothly again.  We had been concerned that whoever came out would tell us that we needed a whole new AC unit and were relieved that it was fixable.  He also reconnected a duct that had not been connected (and was cooling our attic instead of the house) and didn't charge us anything additional for that. We would absolutely use them again.