Pros: too many to list
Cons: process to obtain sucks ass and you WILL be purchasing more after your first
To me, it depends on what you are going to use the gun for. I have a 26" 260 that I play around with shooting steel and paper and a 20" 260 that I hunt with, both with Rem varmint contour barrels...that 6" makes a huge difference in mobility, especially when you add a 9" long can IMO. The velocity loss (or lack thereof) really surprised me when I had my 20" gun built this past summer. I am running 140 amax's at 2825fps in the 26" gun and 2775fps in the 20" gun.