Defense:
Everybody knows the front 4 can rush the passer. What they don't know is they also defend the run well. All 4 of the starters are having Pro Bowl seasons.
The weaknesses in this group are:
(1) Hughes can be a hot head. He's drawn 3 unsportsmanlike penalties this year and got benched in Denver for one.
(2) Manny Lawson who comes in at DE in rotation is susceptible to misdirection ("squirrel!") and thereby dreadful in holding the edge. Buffalo giving up a 10 point lead to KC in the 4th. quarter boiled down to Lawson blowing edge contain on two plays.
The stats show they've given up a fair amount of yards per carry in recent weeks. That's because they've been playing more and more nickel with 6 in the box with Brown and Bradham inside. Against Denver they ran nickel almost exclusively with the MLB Spikes on the bench until the 4th. quarter when Denver was trying to burn clock with the run. Still and all, excepting Thompson's 47 yd. run, they allowed a 3.1 yd. average on 28 carries which tells you something about the line and "B" backers against the run.
The plan worked to the extent that they broke Manning's 52 game TD pass streak and held him to his lowest single game QB rating in 6 years. Inexplicably, Spikes was sitting on the bench even when Denver had the ball near the goal line. They paid for it with Anderson scoring from 6, 1 and 3.
I suspect Manning has been having issues with feeling in his hand. Denver had gone heavy to the run game in the 2 weeks prior making Manning play game manager. He was wearing the glove on the throwing hand on a 60 degree day against the Bills. But that's a story for another day, except to say the "stop Manning is Jobs #1, #2 and #3 game plan" was probably overdone. Manning was not sacked; then again he was throwing quick all day in game manager mode and did not have much to show for it.
The secondary is decent. Aaron Williams is a solid all-around safety; Searcy is a ball hawk. Gilmore's a solid cover corner with ball skills but not somebody Rodgers would avoid. Graham is the weakest link in the starting 11, particularly susceptible to the double move. Little Nickell Roby (aptly named) plays in nickel when quickness is called for and in dime; Duke Williams plays in 3 safety nickel and dime and is a hitter.
In general, they don't do anything particularly fancy; they pretty much just line up and play. They like to blitz Bradham up the middle occasionally or a DB off the edge from time-to-time, but that's about it.
Lawson and Graham present match ups to attack. Rodgers can probably get Searcy out of position with eye or pump fakes. When Spikes, a downhill smash mouth MLB, plays (if he plays) the middle can be exploited with play fakes but you won't have much luck running between the guards. But if Buffalo played nickel against Manning all day with success I don't know why they wouldn't take the same approach with Rodgers.
In general, these guys play hard every series with seeming disregard for the scoreboard, they pursue every play, and they're all solid tacklers.
Perhaps the worst thing you might say about this defense is they have too d*mn many guys named Williams.
Offense:
Orton has not played as well as his stats. His arm strength is below the NFL average; he can't run; his mobility in the pocket is limited. If you get his feet moving his accuracy goes down. He wants to stand in and throw. He will throw into coverage from time to time. After early 4th. quarter success against DET and MIN, he's been poor in crunch time. With 1st. and 10 at KC's 15 with the game on the line, he threw 0-4, with three of those passes being dreadful. It should go down as the signature moment of futility in the Bills season. Still, he's a savvy guy, he doesn't let a pick get him down, and there's no quit in him...that can count for something on a given day.
A very good running back group is depleted by injury. Spiller's out with a shoulder. Jackson's playing with a groin...he's still got the glide but has lost some punch. They like to screen to Jackson...a lot. I don't know why they don't use Boobie Dixon more...he's a load with surprisingly quick feet. Bryce Brown has been unimpressive. It's not a good look for an offense designed for run-to-set-up-the-pass.
The receivers are a pretty decent group. The rookie Watkins has flashed regularly but he's been hobbled with a few nagging injuries (ribs, groin); he went to the sidelines after taking a shot late in the Denver game; it looked like he might have aggravated the ribs . Woods is a decent possession receiver; good hands, good routes, OK speed, nothing spectacular. Chandler is a decent short-to-intermediate throw TE who won't run away from anybody (except maybe Hawk

)...more a block some/catch some old school TE. The #3 Hogan out of the slot has a just-a-guy look about him, but they call him "7-11" because he always seems to be open. This crew would look a lot better with some better QB play.
The O-Line is pretty good at both OTs and C; the Gs are a bit suspect.
Summary:
The Bills defense has the capability to keep the game close. Will they finally give up the ghost with their playoff hopes worn down to a thread? We'll see. The Orton offense is disfunctional enough and banged up enough to make it tough sledding for the Bills even against the Packers' less-than-stellar defense. I will say this...if Orton is not pressured and can just stand in he can move the ball.
In the end, the difference in the level of QB play between the two teams will be the difference...again. The O-Line now has the chance to prove what they can do. This is not Atlanta's front 4, and Rodgers wants to go down field always.