While both the Redskins and Dolphins struggled in 2011, Miami actually appears to have a bright future. The 'Fins boast solid skill position guys and solid offensive linemen, which will obviously be attractive to a guy like Manning.
Miami boasts two running backs who could turn into cornerstone-type guys: Reggie Bush and Daniel Thomas. Bush appeared to finally figure things out at the NFL level in 2011, rushing for a career-high 1,086 yards on 216 carries (5.0 yards per carry), with six touchdowns. He also caught 43 passes for 296 yards and another score.
At receiver, the Dolphins have the supremely talented but troubled Brandon Marshall and a solid slot guy in Davone Bess. When he is focused, Marshall has the potential to be one of the best receivers in the NFL. What Miami needs is to add a solid No. 2 option at wideout, which would allow Bess to move to the slot permanently.
On top of all of that, the Dolphins have one of the best left tackles in the NFL in four-time Pro Bowler Jake Long. Manning could feel comfortable with Long protecting his blind side. Miami also has the No. 8 pick in the 2012 NFL draft to add talent to the offensive line that would help keep the 35-year-old signal-caller upright.
While the Redskins have a few nice pieces, the Dolphins are far better positioned to compete now. I think Manning will go to the place that gives him the best chance to win.