We use Lorex/Flir. They've been close to 0 degrees. Still work well after 2 years or so. They want you to pay for the cloud storage, but last I checked, you can't back up all 16 or 32 cameras. We have 2 NVR's and certain cams don't record during certain timeframes to save data. The nvr holds like 5 days of footage for 16 cams each. Audio works ok, but we keep it off for legal reasons. (At work)
Phone app is decent for live viewing.