keys versus combination locks

[Ward Hubbell]

Does anyone have experience going keyless on your rental properties. any downside to converting my units to electronic combination locks and ditching the keys all together?

[Ian Dikhtiar]

I have a duplex in another state. How would I do this remotely? Say, I hire a guy to change all door locks to a certain model(s). Is there a way for me to get access to those locks through apps? 

Schlage that @Nathan Gesner recommends seems like a wonderful solution, but it doesnt seem to have that type of software that would allow me to control/change/reset/open/close those locks. Or does it?