Karma is big on sharing, so you can't stop other people from connecting to your device. But the bright side with that is you'll also be able to join other Karma hotspots and carry over your data. Of course, you'll still need to shell out $150 for a Karma Go hotspot of your own, on top of service fees.

"We'e been thinking from the start, pay-as-you-go is a good model if you don't use it [Karma] too often," said Karma CEO Steven van Wel in an interview. "But slowly, as we come bigger, that model tends to become expensive." As he explains it, Karma always intended to offer unlimited plans, it just had to build up its software and find a reliable partner. It wasn't exactly possible with Clearwire's WiMax network, which Karma's first-gen devices used, but Sprint's LTE network is another story. Van Wel notes that the unlimited speeds can also improve eventually, as Sprint beefs up.