Most significant signing: Keeping safety Devin McCourty trumps the two-year, $11 million deal for defensive end/outside linebacker Jabaal Sheard, as those rank 1-2 on the list. As a captain who has elevated his game to now be considered one of the best safeties in the NFL, McCourty is one of the team's foundation players and his presence should continue to grow both on and off the field. The Patriots faced significant competition for McCourty, with the Eagles, Giants and Jaguars all making a strong financial push to sign him, and McCourty was prepared to depart until the Patriots stepped up at the last moment in the process. Sheard, formerly of the Browns, is a Patriots-type player in the sense that he's big, physical, tough and versatile.
Most significant loss: This one isn't too hard. When you lose a cornerback the caliber of Darrelle Revis, it seems safe to say the secondary probably won't be as good as it was in 2014. The Jets, with salary-cap flexibility and a motivated owner who wasn't going to be denied (he declared his intentions in December when Revis was still under contract), pushed the envelope to sign Revis away and add another chapter to the rivalry between the teams. With Revis and fellow starting cornerback Brandon Browner (Saints) now elsewhere, there's a rebuild in progress in the secondary that was a strength of the team last season.
Biggest surprise: Everyone knew that Revis' future with the team hung in the balance, but the club's decision not to pick up Browner's $2 million roster bonus caught some by surprise. Browner's salary didn't seem out of line with his production, but the Patriots made him a free agent regardless by not picking up the bonus. This was likely a result of not knowing if they'd have Revis and thus not being able to fully commit to the press-man coverage that is Browner's forte. So our read is the Patriots probably didn't want to be locked into a scheme-specific player at significant dollars without knowing if they'd be playing that scheme.
What's next: The Patriots haven't addressed the interior offensive line (re-signing Dan Connolly would seem to be a priority), and they've also been checking out pass-catching running backs (maybe Pierre Thomas catches their eye?) and linebackers who project as core special-teamers (they visited with Andrew Gachkar before he signed in Dallas). Cornerback is obviously going to be the top area to watch, but there doesn't seem to be any surefire answers in free agency at the position.