I have been lvl50 for a while and must admit I did start off as a Deception Assassin just like 90% of Assassins that play this game. Sure they do 'Good' damage but I dont think the tree and or spec is optimized enough. I realized this at around lvl46 or so which is when I started looking at other specs; Madness to be exact. Course playing as deception for so long made me a bit skeptical at going a completely different route and adapting to a new play style. In my opinion Madness does way more damage than deception. Sure the rotation and amount of skills available is a lot more, along with the skill required to play Madness effectively.

Deception= Voltaic Slash x2 --> Shock

Madness = (Depending on how you want to open or start) Spike --> Shock(Trigger Unearth Knowledge) --> Death Field --> Creeping Terror --> Discharge --> Thrash(Till Raze proc) --> Rinse and repeat

I have also notice the amount of damage Thrash does over Voltaic Slash and it is a considerable amount. Not only just the crits but the base damage. I have been able to his for 1.6k dmg with both strikes of Thrash(Non-Crit). With Crits I have seen it go up to 1.8k to 2k. Course I am not stacking all power I am mixing Power and crit because of the fact that Raze needs a melee crit to proc. Either way this is just my observation after playing both specs and doing a few test runs with both.

Im also a Madness Assassin and I prefer it to deception.

It seems to be more damaging (Although until a dmg meter comes out we wont know for sure)

Also out of interest do you use dark charge or Lightning charge?

as I know DC is aimed for a tank but the extra 4000 armour/ability to use guard seems to outweigh the dmg bonus you get using LC :S

Im also a Madness Assassin and I prefer it to deception.

It seems to be more damaging (Although until a dmg meter comes out we wont know for sure)

Also out of interest do you use dark charge or Lightning charge?

as I know DC is aimed for a tank but the extra 4000 armour/ability to use guard seems to outweigh the dmg bonus you get using LC :S

I use LC because of the Raze Talent in Madness and the extra 3% crit from Charge Mastery. I would advise the use of LC when playing Madness, not only because it is intended for such but it adds to your damage which is based off of your DoTs and your heavy hitting Thrash hits. In PvP i often come out with a minimum of 9Medals and sometimes 11 after switching to DC midway through to gain some of the defender Medals. But yes like you have said since the damage meter isnt out yet I cant really speak on the damage but from what I have seen in PvP and PvE Madness is indeed the way to go.

Im also a Madness Assassin and I prefer it to deception.

It seems to be more damaging (Although until a dmg meter comes out we wont know for sure)

Also out of interest do you use dark charge or Lightning charge?

as I know DC is aimed for a tank but the extra 4000 armour/ability to use guard seems to outweigh the dmg bonus you get using LC :S

You're probably talking PvP here whereas the OP is more than likely talking about PvE.