Beta testing is normally a short period of time when select users test the 99-100% completed product.
The User Acceptance Testing is the final step-by-step walk through of the product before the users sign the last contract, ending all further commitments not stipulated in other contracts.
So, Beta is Short and Sweet.
However, most gamer's will be sad when we reach that point... Unless they reveal the New York City game with limited use of voxels (clearing a collapsed section of a subway tunnel.) AND use of ziplines between building(s edit) because street level and below is pure hell!