There was a long thread on TOS with one of their lead engineers talking about barrels.
Basically he said he did not recommend fluted for suppressor use. To much material is removed from the barrel.
ELW barrel is better than standard because the material removed adds no structural Integrity. So you get a barrel that whips the same at a lower weight when using ELW.
I don't have any science shit to back up what I listed. But it came from a guy who gets paid to do this stuff so I took his word for it.
I went with the 11.5 ELW barrel and a 10 KMR-A and I gotta say the balance of the rifle is outstanding. I also use a specwar k on the end. I've fired a couple thousand rounds maybe more. Zero malfunctions and the groupings are well within considerable for what you pay for.
It does get hot though. You need gloves or rail covers if you're a high volume shooter. Cools quick but I can feel that heat when I use the magwell, when I get my can smoking hot you can feel the heat. It's nothing to be concerned about just a observation.
Get the ELW and you won't be sorry. Play with it without the can on and you will be impressed with its balance.
Edit -
BFH, this is debated to death but he also talked about that. He said for a high volume of fire talking rounds per minute it will last longer but we're talking thousands and thousands of rounds here. For low volume most barrels will rival the life span of the barrel. So if you're doing constant mag dumps or have a happy switch you may want to consider this. Really comes back to the ammo debate. If you shoot enough to shoot out your barrel its not an issue either way.