Since version 1.4, Skim is not able to open PS-files any more. It's trying to convert and does not do anything else. I hoped, it would be fixed in 1.4.1, but it isn't. There is nothing written in Console.app exept for the killing of Skim I have to do (16.01.13 12:24:43,687 com.apple.launchd.peruser.503: ([0x0-0x4e54e5].net.sourceforge.skim-app.skim) Exited: Killed: 9) since after stopping the conversion, Skim isn't usable any more. When switching back to 1.3.22, it's again working correctly.
I'm using Skim on a 17'' MacBook Pro from beginning of 2009 under Mountain Lion.