Do you really need portability? And for what purpose? As someone else mentioned, you can run long lengths or airhose without a problem. If you have an occaisional need to use a nailer in other locations then perhaps a small 10 gallon air tank or a cheap pancake compressor would do.
It's not so much an advantage, but the ability to run larger compressors that are 220v only. The first two compressors you mentioned are about the max you'll get out of 110v. Anything larger will require 220v.
This would allow you to run a wider variety of air tools.