There is an interesting article on Surrendering Pressure at ProFootballFocus.com. The Green Bay Packers are ranked No. 12 overall, but since they got better over the course of the season, I'd give them a higher preseason 2011 ranking. LT Chad Clifton got better throughout the year, and RT Bryan Bulaga had some regular season stinkers (he was awful in their Week 17 win over the Bears) before settling down for a solid postseason run.
They give high praise to the Packers when they leave an extra blocker in:
The Super Bowl champions led the way when it came to skill players being kept in to block and doing so effectively. None who stayed in on more than five occasions ended the year with a negative pass blocking grade. Maybe more teams will consider carrying three fullbacks on the roster if players like Quinn Johnson, John Kuhn, and Korey Hall can improve your pass protection this much.
I'd also point out RB Brandon Jackson and TE Andrew Quarless. On the other hand, once Mike McCarthy had confidence in RB James Starks as a runner, he would leave him in for pass protection though he wasn't nearly as good as Jackson at blocking. Having the extra blocker is nice, but giving the defense an extra offensive weapon to worry about is an advantage too.
While QB Aaron Rodgers had some criticism in 2009 for holding the ball too long and taking sacks, he came in ranked a respectable No. 11 for "QB-invited pressures" in 2010.
I haven't read much, if any, criticism of the pass protection after the 2010 season. It looked much improved, and the stats appear to support it.