Pros
Flexible timings. Some times you get interesting and challenging test cycles.
Cons
Many times no clear instructions in the overview. After you spend lot of time testing and find bugs, they get rejected as they were known issues to the client but they never attached the known issues lists to test cycle. No value for testers time and their efforts. Testers are taken for granted. Client who evaluates the issues is not informed clearly about utest rating policy and many times the WAD bugs gets rejected with different reasons. Many times when you are half way through your testing, they inform you that the links are wrong or devices are not in scope. All your effort is wasted. It's very challenging for the testers to remain motivated with utest as the management attitude is not reasonable towards testers.