You can network boot them too, which is way more convinient. RPi3 can do it natively, the former ones need an SD card, but since it's only for the bootloader, it'll survive much longer.
Last time I read about this [1], the firmware had some issues that prevented the boot process from working 100% reliable. Do you have any experience with network booting the RPi?
Yes, but I only have 2 devices that network boot. One is with PoE, one without. Both work fine, but I don't have the need to reboot them every other day and the network is not a complex structure. Filesystem is with NFS.
[1] https://github.com/raspberrypi/firmware/issues/764