Need to hit 28 for Burn and 32 for FS... well maybe a bit after to get slots in them
SS will be better in the end, but it does bloom later than DB.
Unless it is a dedicated AE farming character, I'll say play the Dual Blades if your enjoying it more. For most PVE content the difference really isn't that much anyways.
Ok need a few comments on this one. I have 1 of both atm. My DB/FA is level 41 and moving along alright. But then I read somewhere that DB/FA is not very good so I decided to try out SS/FA but thus far is a much tougher spec to level, level 26 atm. Am I doing something I am supposed to be doing that makes the build a bit easier or is it just hard till a specific level or gear issue.