Besides telling if a device is live or not, not that I know of. The one major issue is that you can't have an MRI, although if I'm in a situation where I can't tell a doctor that I have them, magnets being ripped out of my fingers is the least of my worries. If need be, I could have a doctor make a small incision and take them out. And I do have to be careful not to hold on to powerful magnets for too long, or it will crush the skin in between the two magnets. Other than that though, there's no real downside. They're off to the side so it doesn't affect my grip, and once my skin finishes healing they'll be unnoticeable.

The upside for me is the qualia of sensing emfs and having them as toys to play with. I treated the decision like getting a tattoo, where my personal rule is I have to love a design for a continuous year before getting it. I haven't settled on a design long enough to get a tattoo, but I had planned on getting magnets for about a year and a half so I went ahead and did it.

Having extra senses is pretty cool.