+1 to the Yong Heng, it's noisy but not deafening, and I have sensitive hearing (Hyperacusis).
I don't hang out with the YH while its filling though, only go in to vent the water trap half way through my fill, similar to Jim. I also have a dedicated spot in the garage for it and the water bucket. which is out of my way and not an inconvenience, for those that lack space, I would lean towards the gx cs4.
When my YH kicks the bucket, I would consider the gx cs4, but not until users report exceeding 40 hours of run time on it consistently, until then the YH type of compressor is tried and true, with cheap parts if one opts to rebuild. Construction is simple enough that most guys could make sense of disassembly and re-assembly, and the compressor itself is relatively inexpensive, I paid $200 for mine, sadly the price has gone up a hair on them since then.
-Matt