I ordered this die in 6.5 Creedmoor last week with a Forster .289" bushing, just got here yesterday. I put in a SAC bushing to see if it fit, and while it does, there is quite a bit of vertical space since the Forster bushings are a bit taller. Even with lowering the top cap all the way, there's still space, so it would likely not size the full neck and be of an unknown amount.
Anyhow, I tested sizing with multiple pieces of 1x fired Lapua brass and the neck concentricity has been great (<.001" runout on most, max was still <.002"). It's also a very smooth die. The inside of the die and their neck bushing has a mirror finish. The vertical laser etching on the die threads combined with their new Accu-Ring works great for getting the desired headspace.
I'm going to load these cases up later today and will report back with bullet concentricity as well. So far it's looking like a solid FL bushing die.