Have used the xxxtra with the M8 switch since it first came out. Never had a problem with glitching or fading or anything. Only problem with the xxxtra is being able to see the very small arrow to change frequencys.
Of course the real problem is like the first time I got it, I had to change channels 3 times that night to avoid conflicts when people showed up and couldn't change. Never had that problem before when I had a single channel.
Buy it, you won't be sorry.