Once a decision has been made, do they send you the decision letter and your passport/passport with visa back together? Also it sounds like they do not tell you whether you are successful or not in the decision email - you have to wait for the letter to turn up. That just sounds mean to me...
Currently trying to pass the time and not spend too much money!
The email just says that a decision has been made, and usually is followed up shortly with another email with the tracking info inside. You might already know it, because you will have purchased the label already, but they confirm the tracking number.
Then the package arrives with a decision letter and your passport, which has the vignette inside. Once you go through UK immigration and get stamped in by them, you go to the post office to pick up your actual visa, which is a biometric residence permit card.
Some people have said that the package comes back with just your letter and passport, and your docs come back in another package, but mine all came back together.