Originally Posted by
Vaelicious
Mutilate, which is one of the two skills assa rogues use in their rotation requires dagger in both main and off-hand, so Heavens Fall and Lungbreaker are BiS.
Combat on the othe hand prefers a fast axe or sword (gunship axe being BiS) due to hack and slash talent making them able to proc slow big main hand hits with their off-hand as long as its sword or axe.
As for OP youre best off getting STS, not only will it give you biggest dps increase, its also one of the hardest items to get due to huge competition and the fact it drops from RS 25hc which most guild arent able to do. Lungbreaker on the other hand is very accesible and theres no competiton on it since its only assa rogues who need it and its an unpopular spec of unpopular class.
Also should you switch to combat your STS will still be BiS