I use HCO Spartan GoCams. So far pretty pleased with them. Regarding the above comment, I really don't think someone should be concerned about potential ban or whatever from F&W. Most folks using these are in all likelyhood, a good distance away from the cams themselves.
Yes you need cell coverage, as they suggest three bars. However I have had one of mine working showing one bar for a short period. Pretty nice photos. The trees in the first photo look tilted because a bear played with the cam.