About a dozen years ago a friend of mine had a 47 Atlantic down in Fla. He and his wife used it as a live aboard. My recollection was that is was an unusually roomy boat and appeared to be well built.
According to the McKnew/Parker guide it was in fact designed by Jack Hargrave as the 46 Prairie. The company went out of business and re-emerged as Atlantic 47. It seems that most of Jack Hargraves' boats were understated as to size since it had an OAL of 46'9" and it was sold as a 46. Under the new name it still was 46'9" but was called a 47. As a comparison, the 1981-1984 Series 1 48 MY was (is) 48'8" and is called a 48, which was standard procedure for Hargrave and Hatteras. I suspect that the Atlantic's were not as heavily built as the Hatteras. An example is that the listed base weight of the 48 Hatt is 45,000 lbs, while the 47 Atlantic is 41,000 lbs and another thing is that the Atlantic has a 16 ft beam while the Hatt has 15 ft. More beam, almost the same size yet much lighter.
Insofar as performance, my friends boat never left the dock for over 2 years and therefore we had no clue as to speed, handling etc. I can say however that it was the perfect platform for some pretty good dock parties. If I was still in the market for a MY of that size range and there were no decent 48 Hatts around, I would probably consider a 47 Atlantic......maybe....
Walt