In my opinion, the only advantage nrf24 has, is that it's cheap..
That said.. A lot of clones exists of the nrf24 chip, that sometimes make it a hit and miss if it works.. Also, it operates at 2.4Ghz, and RF penetration on that frequency band is not as good as on lower frequencies of rfm69.
RFM69 operates below 1Ghz, which are better at penetrating walls etc. rfm69 also have encryption build in, that you could use.. Only detail is that it's a bit more expensive to buy, but the coverage of the network should (in theory) be much better, and can be made more secure
I started out with NRF24, but consider switching to rfm69 radios for all my sensors, when I come around to it
