>> Gimp it still didn't support adjustment layers for non-destructible editing, which is pretty much a show-stopper. Packages get used when they lead the way in a given field, most of the OSS design apps I've seen are just playing catch-up.

So which is it? Gimp isn't good enough because it doesn't provide feature for feature compatibility with PS or because it doesn't do something different? You just claimed both. It has a different workflow than PS so yeah as long as you try to keep using it like ps it is going to compare poorly.