On the surface it seems like a pretty solid hire.

• Has had success at pretty much every stop of his coaching career:
  • Division III (1993-1995)
    • HC of Plymouth State University. Resulted in a 25-6 record, 2 playoff appearances and 3x conference CoY.
  • Division I-AA/FCS (1996-2008):
    • DC of Brown University for 2 seasons (1996-1997) with a nation leading 28 interception his 2nd season
    • DC of UMass for 2 seasons (1998-1999). Resulted in a DI-AA Championship (1998) and 2 conference titles.
    • HC of Northeastern University for 4 seasons (2000-2003). 27-20 overall record. 1 conference Championship, CoY and playoff appearance in 2002 with a school record-setting 10 wins.
    • HC of UMass for 5 seasons (2004-2008). 43-19 overall record. 3 playoff appearances, 2 conference championship, 2 conference CoY, and FCS Runner-Up (2006)
  • DIVISION I-A/FBS (2009-present)
    • DC of University of Maryland for 2 seasons (2009-2010). Horrendous 1st season, but impressive improvement the 2nd season: #39 in total defense, and #18 in turnovers. The Terps' defense also dominated ECU's 12th-ranked offense in the 2010 Military Bowl.
    • DC of UConn for 2 seasons (2011-2012). Finishing #10 in total defense in his 2nd season (2012)
    • DC of Boston College (2013-2015). His 2015 defense led the nation in total defense and finished in the top 7 in every defensive category.

Just reading a couple of articles on Don Brown, it seems like he runs an ultra-aggressive defense that supposedly "blitzes nearly 85% of the time." His former players describe him as a defensive "mad scientist" and his defense as "organized chaos." It also seems like the success of Brown's defenses depends on a really competent secondary since they blitz so much. As a pure DC, Brown has some chops schematically. Recruiting-wise he seems to be lacking. None of the defensive classes at Maryland, UConn or BC really stood out.

I'm not sure how he'll perform against Urban's spread offense since there really wasn't anything similar in the ACC. However, Brown (as HC of UMass) did have to defend against Chip Kelly's offense while the latter was OC of New Hampshire (2004: 38-21 UMass... 2005: 34-28 New Hampshire... 2006: 28-20 UMass).