Geroge Gillett is a very successful (American) businessman, a chairman and director of several companies in which the Gillett family holds interests including the Montreal Canadiens, arguably the most successful NHL team of all-time, and he is a member of the Board of Governors of the NHL.
As for whether or not he will be good for the team, some owners prefer to oversee the management of team affairs (Mark Cuban, Jerry Jones, Dan Snyder, Harold Ballard, Al Davis, etc.) while others understand that their strengths lie as businessmen and not as the team's General Manager. I see Mr. Gillett as the latter, not the former. A good thing, in my opinion.