I'm a little surprised by the number of Jeremy Jacobs responses, but I'm coming from a Buffalo perspective. Jacobs is a native Buffalo, NY resident that has pledged and donated millions of dollars to local charities and universities including Roswell Park Cancer Institute and the University of Buffalo. Recently, the state-of-the-art Jacobs School of Medicine and Biomedical Center at UB just opened.
Jacobs has provided steady ownership to the Bruins since 1975 during which they've been highly competitive and have won Cups. Most owners want state and local subsidies to build arenas, but Jacobs built TD Garden out of his own funds. There has much discussion about the Buffalo Bills needing a new downtown stadium. Jacobs has stated that he would build the stadium with Pegula when the time is warranted.
I'm not familiar with his Boston dealings, but I'm sure he has made many charitable contributions. An owner should provide the team with the resources it needs to be competitive. Jacobs has done that for Boston. Whenever he is interviewed he acknowledges that the Buffalo fans are great, but he loves his fans. Buffalo has been lucky to have an owner like Pegula. I guess we appreciate him more after the last few owners we've had (Rigas, Golisano and even the NHL itself). I guess it all comes down to your perspective.