Well since there were so many great replies, I will reply in case anyone in the future is curious.
I bought the IPC-HDW4421C from ali express.
My current setup is a HIK 2032 which I have recording to NAS. From the cameras interface, I am able to login to the camera and access recorded files and play them back. HIK makes this very convenient. This is a major plus when I am not connected to my LAN. I can access the camera and view/download footage remotely.
DAHUA does not enable playback from the cameras interface. Apparently, if you buy one with builtin sd card slot, the camera has a playback tab. This is a very inconvenient. I can record to NAS or ftp but playback is not an option in the cameras interface. Big bummer.
So unless you are using third party surveillance software, this camera is not a good choice.
Hikvision firmware is a great option for people not running surveillance software.