They are very professional at what they do; I have never experienced any issues with them during my time working there or since we transitioned out of that role! There really isn't anything specific about this vendor as far has customer service goes but if your looking into having someone work in house just make sure its an internal candidate who will be able transition well once hired!! Highly recommend considering using these guys - great people & incredibly knowledgeable when doing consulting engagements around Salesforce products/features (not only SFMC).