A few things you may wish to do. Search the web very closely using terms like trail cameras, deer cameras, and game & trail cameras. Ask very pointed questions concearning speed of the unit, wheather the unit slows down using larger memory cards, how many batteries and what types the electronics require, the size of the unit, ect... Ask this from multiple producers including those you listed. If they have a solar panel, ask why one is necessary. Many of the newer can run for a considerable length of time just on a 9 volt and the camera's internal batteries. Don't be afraid to ask hard questions, and EXPECT full answers. Don't rule out the homebuilt either. They can be higher tech than many of the commercial.