X2 on CFM being king. I'd rather have a 5 CFM compressor or other source of air rated to maybe only 80 PSI than a 300 PSI compressor rated to 1 CFM (cubic feet per minute). 5 CFM is actually a lot of air, only large compressors are capable of pushing that much air out which means the tire will be reinflated very quickly. A 5-6 CFM source of air can reinflate four 35x12.50 tires from 7 psi to 25 psi in about five minutes. A 1 CFM compressor rated to 300 PSI would take 30 minutes to refill the same tires.
A typical small noisy Autozone compressor is likely rated at around .5 CFM which means it'd take something like 45 minutes to reinflate the tires.
I used to have a belt-driven York air compressor I installed into my previous TJ and it put out 6-7 PSI. That thing kicked butt. That TJ was stolen and my newer model TJ wouldn't have been as easy to install a York compressor into so I put a C02 tank system together. It puts out a huge volume of C02 out and refills all four of my still 35x12.50 tires in about the same 5 minutes... total for all four. I bought the aluminum 10 lb. C02 tank for about $80 and regulator for about $50 on the Internet and bought the rest of the fittings locally at Home Depot. Even Harbor Freight has most of the small misc. parts needed. I think I have maybe $160 total in my C02 tank. It last 5-6 trips and costs me around $15 to refill locally. I like it because it's FAST and it's QUIET. Those small compressors are like buzz-boxes that are loud enough to wake the dead and everyone else in your campground if you decide to air up early in the morning.
