Yeah I did a lot of forum reading... to see what people were saying about the 4 piece. I came to the conclusion that even though it may help, it didnt seem like a big enough upgrade/huge 4piece gain...to where I would want to take the heroic marks that are going to be in such high demand. After all the guildies in my token tier have theirs and its going to off spec, I will ask for them to go from my 2 piece to my 4 piece and then spend lots of time on the dummy figuring it out for myself.
Until then, I will just go after the off pieces and get my 2 piece t10 and be very happy when someone else completes their 4 piece and does some major pwnage with it.
With that said....the 4 piece is more beneficial for combat btw. Ive noticed already that having that proc sometimes...helps my rotation but sometimes makes it worse too because I end up having no choice but to clip a lot of my envenoms or I waste energy. I would rather not waste my energy and clip my envenoms but pack a bigger punch in my hits, I guess.