First time buying a car with Colonial, and frankly with any GM dealer. Didn't know what to expect, but it was fantastic. From start to finish, couldn't be happier and was so much better than what I've seen from Mercedes and BMW. Contact was efficient, went in for a test drive which was quick and efficient. They didn't waste your time. Getting the paperwork done and picking up the car was also incredibly efficient. And pleasant. No push for add-ons and wasting time in the office. Would recommend Paul Rowe and Brian Mahan to anyone.
As a side note, the new 2018 Buick Enclave is fantastic. Switched over from the Mercedes GLS450, and zero complaints so far.