I see alot of major problems were addressed in V5, basically a really nice V4.9
I'm noticing a few bugs, but this seems like a real replacement for v3.x.
It's nice to see QuickProofs are back, but the processing pane reports their estimated size incorrectly. Wasn't this an existing v3.x bug? The processing summary says the resulting file size will be ~12 MB from 1DsII files when they actually end up being < 1 MB.
Tabbing through editable fields in the Details pane is partially broken. I can't tab from sharpening amount to radius, for example.
I've seen erratic behaviour in the processing queue. Sometimes when I have more than 100 files in my queue I have difficulties deleting all of them. If I select all of them (command + a) delete will not do anything. The work around is to shift-select a range of images, leaving at least one image unselected, and delete those. Then deleting the last file works properly. Occassionally I'll need to relaunch the app to delete the full queue.
And finally, I've noticed a few times where when switching to different folders in the Library, the browser reports "No collection selected". Switching to any other folder reports the same message. All folders seem empty. Relaunching app is required to fix this situation.
These last two bugs don't happen often, but when they do it's a pain.