The most important position for any football team is the quarterback. A good QB is the difference between contending and not contending, a great QB is the difference between making the playoffs and winning the Super Bowl. The New England Patriots have the best quarterback situation in the division, followed by the Dolphins, Bills, then Jets.
Buffalo Bills: Tyrod Taylor, Unproven
Rex Ryan is going the Seattle route for trying to contend. Use a QB who will won't turn the ball over while the running game and the defense do the heavy lifting. Taylor provides mobility and the Zone-Read to the offense, which is particularly why Rex Ryan hired former 49ers OC Greg Roman. While Ryan the Bills haven't formally announced their starting QB, it's fairly obvious at this point that Taylor is their guy. It's hard to rank Taylor for QBs, because he's hasn't proved to be either good or bad. When you consider the other option, EJ Manuel, this competition hasn't been close. Except to see this guy in Week 2 when the Patriots play the Bills.
Miami Dolphins: Ryan Tannehill, Average Starter
The Dolphins gave Ryan Tannehill a contract extension in the offseason to lock up their guy for the foreseeable future. Tannehill has had to deal with below average OL and WR play, but the team has invested into improving those areas the last two offseasons. To me, this is a make or break year for Tannehill to prove he's more than an average starter at QB. When your primary division foe features one of the greatest QBs to ever play the game, average is not good enough to win the division. Tannehill's greatest weapon is the Zone Read-Option and coupled with an underrated RB in Lamar Miller could give the Dolphins a solid rushing attack. The receiving corps has added Jordan Cameron, Kenny Stills, and DeVante Parker and lost Charles Clay. I believe they got better at WR, but got weaker at the TE position. A receiving corps headlined by Stills, Parker, Cameron, Miller, and Jarvis Landry should be enough for Tannehill to put up big numbers on offense on paper. Whether he does remains to be seen.
New England Patriots: Tom Brady, Elite
If you have a Mount Rushmore of Greatest Quarterbacks of All Time, Tom Brady has to be on that. Despite talk about his demise, Tom Brady ascended to a whole new level and dominated most of the competition en route towards a 4th Super Bowl victory. Twice in the postseason he carried the Patriots to comeback victories, throwing more than 50 passes against the Ravens and Seahawks. Brady's receiving corps did not experience any turnover and even added another quality pass catcher in Scott Chandler, which is even more of a reason to expect Tom Brady to put up even better numbers than he did last year. Brady takes great care of his body and has discovered the magical properties of Avocado ice cream. I'm not certain what will happen with his 4-game suspension, but I don't want that to permeate into this post. I expect Brady to put up big numbers and win the division and home field advantage.
New York Jets: Ryan Fitzpatrick, Good Backup
If you have Ryan Fitzpatrick on your team and your starting QB goes down, Fitzpatrick can keep you in the game. He's not a QB that can lift a bad team into the postseason, but at the same time he can keep your postseason hopes alive longer than most backups. With the unfortunate incident that happened to Geno Smith, I actually think Fitzpatrick is an improvement for the Jets at the QB position. Fitzpatrick has a solid receiving corps highlighted by Brandon Marshall and Eric Decker. While the Jets receiving corps doesn't stack up against the other 3 teams in the division, it's definitely a workable cast. Even if Fitzpatrick gives the Jets a solid season under center, they need to find a QB who they can rely on in the future. The 2016 draft has a much better talent pool for QBs and the Jets will likely have some options to choose from.
While I believe the Patriots will win the division by a sizable margin, all six of the division games will not be a cakewalk. The division is packed with teams I think are middle of the pack in the AFC. While I don't expect the Bills, Dolphins, or Jets to get a playoff spot, they are not easy outs for any team. While people will knock the Patriots for playing a "weak division", the AFC East is very competitive and could luck out facing the two weakest divisions in football in the AFC and NFC South. The Patriots need to bring their A-Game in order to win any of the six division games and if they end up blowing out their opponent because the opponent didn't bring their A-Game too, so be it.