Don't have any PSP garments to compare, but just tried a breath test on a NeoShell jacket and it didn't pass (I could feel a very slight amount of air getting through, but I couldn't breathe). It felt more breathable than my GoreTex Active jacket, but not by much (not a scientific test by any means, but good for head-to-head comparison).
CFM measurements from manufacturers are questionable though, since there isn't a standardized test (like there is for waterproofing). Your question could probably be better answered on the BackpackingLight forums, those guys are really picky about their gear and a few have designated setups to test breathability.