i would shop for a inferred and look for the longest video times allowed by the product...meaning the longer video it will take would probably sell me. definitely a card spot as well as internal memory. also i would google it and see what everyone else has said about them. ( i was gonna buy a feeder motor, almost opted fer the $90, but turned out the $35 was more bang fer my buck) and warranty, the longer the better. ask if additional displays are available, cause 4 days after the warranty goes out, so will the display. look for something you can hook up on the net to watch or down load, cause the gas will pay fer it. i like to go out and check mine, but there are times where i'd rather just pop em up on the net. gl