Just to clear up any doubts and misconceptions. Does SA Critical Damage increase damage from dagger skills like backstab? And another note: For a pvp>pve dagger, going with SS w/crit dmg better than BO w/focus?
My lvl 48 AW hit for 5795 using Backstab on a mob with her +4 DS w/focus in the Cata's the other night. Highest Crit I have ever got since C5 and that's with a noob.
Focus is the best for PvE by a long shot, it increases crit on specials and makes you do so many crits with normal attacks that you can tear a mob to shreds in a very short period of time.
critical damage affect skills like backstab yes. not only little, pretty much tbm. I have played both focus and crit damage daggers for C, B and A grade, and well...critical damage is a lot more fun. and for PvP its a LOT better, cuz its with you skills you will kill your oponent, not with normal hits. and if you compare a DS(focus) vs CD(crit) its like 1000 dmg on X vs 1500 dmg on X. so its a lot more.
and even for PvE, I wouldent say focus is THAT much better, it is better, yes, you get a more steady flow of HP from VR, and a more stead damage output, but like I said befor, its a lot more fun with crit damage :)
(also remember all crit damage daggers have more base P.attack then the focus daggers. so not only will your skills do much more damage, you normal hits will do a bit more as well.)
anyway, I have decided to go with Critical dagame on my dagger. lvl 61+ TH. I would have picked a SS CD if I where you.