Caller ID is supposed to work, but I haven't made it work with Magic Jack. But it doesn't work with my home phone either, so I'm not blaming the Hopper.
Caller ID works fine for me, I have regular landline service. I just plugged in my phone line in the back of the hopper and haven't had any issues. It also keeps a log of your incoming phone history.
I'm way off topic but I ran MagicJack for about 12 months, and it was absolute crap. I switched to voip.ms for about $8/month and have a good, reliable phone service that doesn't touch any of my home PC's. FWIW.