Air Compressor decision

To a large extent, it depends on HOW you are going to use the compressor. Hard core 4x4'ers, who need to air up four tires that were let down to a very low pressure for off-road traction, would doubtless need the longer duty cycle. If you're only going to top up one or two tires that have just lost a few pounds, duty cycle really shouldn't be important. CFM is only important if you plan to run any air tools, like an impact gun for changing tires. Even there, if you have a large enough air tank, and let the compressor fill it before using the air gun, it can be a viable work around.