I had a very similar question actually and didn't want to open up another post.
Im using a Longbow (because Zodiacs are longbows and Anet apparently secretly hates me)

And I was also wondering what strings/grip to put on
I bought a Vamp 5/-1 and a Marks +1 (20%) because I got them VERY cheap (like 6k total)... but Im not really sure if they should go for a longbow or if its better for a different type of bow.
A lot of people tell me to use Sundering but Im sorry I just don't know if its really that good. Maybe Im wrong?!? Can someone please give me some insight on what is best to use?
Thanks and sorry for hijacking your post.

I just thought it was better to ask here than start a new thread.