Just a quick comment/word of wisdom to those that opt to participate in the test based on my experience and others guests/CMs I spoke with:
If your band works from the get go, and you do not need to make any changes, i think the testing should be fine. However, if there is an issue make sure you speak to one of the My Disney Experience or MyMagic+ experts at either the resort or guest relations (they usually have dark blue shirts on with the green mickey touch-to-pay/FP+ logo). The front line CMs are not remotely close to understanding how to use this technology and should not be allow to change anything in the system (aside from maybe scheduling FP+) without sign off from a MDE/MM+ Specialist. When they start poking around and messing with stuff on the system's backend that is when the house of cards can fall and it will likely have a domino effect on the rest of your Magic Band features which will likely result in multiple guest relation trips.
(I posted this and my full experience in another thread, but thought it valuable to say here as well:
http://forums.wdwmagic.com/threads/mymagic-testing-update.871028/page-15#post-5676742)