The values listed are the actual gains. The 35% Crit DMG is what's making me hesitate. Currently, my rogue is doing decent damage when doing criticals, but not great damage like some other rogues are. But at the same time, I might not be doing great damage anyways if I can't get past their high defence.
I only care about PvP when I look at gear (so far PvE content has been relatively easy), and I don't think most folks stack defense in a way that would make a big difference. I think evasion is more common (and probably better but I haven't crunched the numbers), so accuracy would help. It's certainly possible that some PvE would have high defense and the pen would hep, but I just don't know about that offhand.