I have a Wilson Combat Recon Tactical in 6.8mm SPC.
The Wilson was a serious chunk of change to pay for a gun for a regular working guy like me, but it's what I wanted and I saved up and got it. And I LOVE it!
A Springfield M1A .308 used to be near the top of my wish list. I have shot one but never owned. (Not an AR, but that's my point of reference.)
Having the 6.8 has helped me get over my .308 lust. If I need to hit harder, further out, I have bolt guns for that. At more realistic hunting distances, for just about any size game I could find around here (except maybe aoudad, which can be found without traveling too terribly far, and are very tough critters) the the 6.8 will do the job in a light-weight, handy rifle that gives me quick follow up shots if needed. I'd still like a .308, some day, but it's moved from the "GOT TO HAVE IT" list to the "yeah, that would be nice" list.
Ammo seems to be much more available than it was just a few months or a year ago. I'm finding it in most stores. Maybe not much selection in local shops, but I can find a box or two just about anywhere. Bigger places generally have higher quantities and more selection, of course. I found a pile of it a Cabela's last weekend.
I know you said you're not getting into reloading, but if you ever do, the brass will be the only hard thing to come by. I'm saving mine from factory ammo and recently bought some new brass from Silver State Armory.
Same diameter bullet as a .270 Win. (.277") so anything toward the lighter end of .270 bullets will work for 6.8. I like the 95 gr Barnes TTSX for just about everything. I shot a 9/16" group with factory ammo loaded with that bullet, shooting under less than ideal circumstances (cross wind, not real comfortable on the bench that day for some reason, etc). That almost duplicated the 1/2" group on the test target that came with the gun. So it's more accurate than I'm going to be able to shoot in the field off hand or off sticks.
Not known as a long range round. My 6.8 is more accurate than my bolt guns at 100 yds, but I have not yet tried it out past 180 or so.