I currently have a 50 assassin, raiding and PvP'ing with the same specc, 2/31/8 - Chain Shock.
What I can say, is that this spec is purely based on damage and very gear dependent. BUT, when some is gathered, it is an extremely fun and interesting spec.
I have more than once been top of damage meters with over 400-500k damage in Warzones, with 10-11 medals each match, and my experience is that the assassin isn't about survival, it's about getting in and out quickly with loads of kills and then Force shroud + Force Cloak.
If you are looking for survivability, you should go Darkness!
The 30% armor is really useless, 4% physical damage taken is absolutely nothing as 75% of the damage taken in Warzones are Force / tech-attacks.
Many people go hybrid specs, that seem liable, haven't checked them out myself. All I know is that deception is about burst and use of cooldowns! It is truly a fun spec and has much to offer if played correctly! But it's all about playstyle I suppose, find something that is viable for you and stick with it until you master it!
//Scythe - Ahto City