Seals are very good but they are notorious loose cannons. I have trained with them alot....and was quick to drop the drama alert when I sensed the seals were deviating from the overall objective out of vanity in wanting to make a statement. With that said....I wouldnt hesitate to have one watching my back in any environment. With some of them you had to watch what they were doing before you followed them.
IMHO Green Berets are far more disciplined and their mission profile is different....but I have only trained with GB's once, so take it for what it is worth.