My neighbors have a Magic Jack and will be going back to a standard, land-line again soon. I talk with my neighbor (friend) almost every day on my way home from work, and I would say 2-3 days a week we will be in the middle of a conversation and all of a sudden she can no longer hear me on the other end of the line. She ends up talking into the phone saying that she
"hopes I can hear her and she will call me back!" When she calls back, it is normally working fine for the rest of the call.
Other times when she is getting a call on her second line, she will put me on hold and the "on-hold" music is
SO LOUD!!!!! It is like, turning your TV to the loudest possible volume say.... level 30 after it had been at level 2 all day! It is quite shocking actually, and can make me a bit crabby
She also has voiced concerns over making an emergency 911 call if the occasion arrives because her young children have turned off her computer's power several times, which means she does not have an active telephone line....... can you imagine needed to call for help, but you have to wait until your computer boots up to make a call??
These are just some things to think about....not sure if these things happen to other MagicJack users, but this is the experience that I know of.