Ubiquiti's cameras are rock solid, both in terms of hardware and software. And if you don't like their software, the cameras provide a raw RTSP feed you can integrate with other open source alternatives. They're not too hard to hack on (official API docs are lacking but their forums are quite vibrant); I've integrated mine with my OpenHab control/display.

I've got a couple cameras that have been running outdoors for years in rain, snow, and heat. At this point I'm just waiting for them to die so I can finally upgrade to the latest and greatest models.