ANT+ Communication and MiRF

Hey everyone,

I just wanted to clarify what the difference between ANT and MiRF are. I know sparkfun has breakout boards for nRF24AP1, nRF2401A and nRF24L01+ - but I don’t understand what specifically their differences are.

Is ZigBee doing the same thing as the Nordic chips? Are there any major differences on that front besides power use?

Thank you in advance!