I took the compressor to the local Porter-Cable service center and they tell me the boxes the P-C compressors come in are NOT designed to handle the rigorous treatment of UPS shipping.
Poor Engineering - Air will leak from the threads of the nipple (as was the case for me) or worse. Pancake compressors due to their top heavy nature can and do rollover, and if this unit rolls onto the gauge side, sooner or later your going to have a major problem. I discovered this design flaw when I plugged my brand new compressor in and a rush of air shot out where the gauge nipple screws to the tank.

The two air ports is really nice in one this size because I can put the compressor underneath my workbench and mount a static line on my workbench for easy access anytime while leaving the other open for longer hoses. These size compressors can make an INCREDIBLE amount of noise, but the Porter-Cable 3hp 4 gallon side stack really keeps the noise level at a minimum.
Don't let the handle fool you. - I know now why most compressors this size have wheels. I wanted an air compressor that could inflate tractor tires and power air tools. I recommed this to any one looking for an good air compressor that stays for the most part in one place.
Darn Good Little Compressor - Short and sweet - this compressor delivers on its promises - it is easy to use, easy to break-in, easy to maintain, and you can't beat the duel air hose inlets. I have found both of the built in pressure gauges to be accurate, and the oil-free motor is quieter than other compressors I have used (although it still makes a good bit of noise). To me, that's portable - I can understand how that would not be the case with everyone, but my experience leads me to believe that this compressor has a very good weight-to-horsepower-to-air storage capacity ratio.
This Portable Compressor is Rugged and Well Built ! - Surprised and impressed! I looked at Home Depot and Lowes and decided to order this air compressor to save the Tax and the trouble of bring it home. The best part is that I didn't have to stuff this big box in the back of my car to bring it home.

Looking at the other brands of portable compressors I really like how well this one is built.
Fantastic Compressor - I was told by others that none of these smaller compressors would do that.
Heavy Duty versatility - I run one in to my garage for airing my tires, and one in the shop for projects.
I will tell you it is LOUD but so are all compressors in this class, and this one is not as loud as my last old Campbell-Hausfeld.
Great General Purpose Portable Compressor - I bought this compressor to run nail guns, air sand and spray paint. It is also handy to limit the pressure to safe levels for your various air tools. It is not as loud as large upright compressors, but it does make a fair amount of noise, although not as much as I expected. I use it with a Souix air sander and it does run longer when I am working.