SI ranks the Metrodome as the #10 toughest NFL stadium to play in (not sure if it's good to be ranked #10 when there are only 32 teams, or if it's good to be recognized in the top 10).
It's fun for the Vikes to have home games at the Dome; it is an advantange. The problem, I think, is that the Dome has helped foster the team's pitiful outdoor record in the past few years. This is partly practical: the Vikes have been built for speed and offense to play on turf, and don't get to fully exploit what they were built for when outdoors. Part of it is psychological: the team seems to lack intensity and confidence when made to play in the cold outdoors (the exception, for some reason, is Lambeau).
The Vikes went to 4 Super Bowls playing in the old Met; since moving to the Dome, the Vikes haven't been to a Super Bowl.
I hope Zygi really gets his way and the new stadium allows the Vikings to play outdoors on grass. We know what it's like in Minnesota in December; now lets make other teams know that too.