New,
There's many items to consider, at least for myself, when considering a network IP camera, but the largest item is how the stream data is sent to the NVR. Since you're not mixing/matching, it's a "you get what you get" item. They may or may not be multicast, they may not offer a certain codec or what have you....I didn't look into the cameras and hardware, it's not something I'd install or support, to be honest, but going off the cut sheet, it doesn't seem like they do multicast, which would be a dealbreaker in my world.
Remember, I install systems as a trade, so the installs I do are far more driven by design performance balanced with budget.
In the case of IP cameras outside: water, dust, and condensation are issues with every camera out there, and in the case of IP, how the cabling connects to the camera, no matter how well the camera is designed, those are considerations I have...not to mention, even if there's a whip off the camera, how sealed is that RJ connection?
My main issue would be the NVR and cameras are a closed system and product....Lorex cameras only on Lorex NVR's and vice versa. While I'm sure someone might try to reverse engineer a driver to try, it's not something I'd entertain.
In the case of EK, look at the list, the cameras listed are both old revisions as well as very widely installed and sold cameras within the pro world. Not saying it can't be done, but I wouldn't count highly on it.