I recently purchased a 6.5 Creedmoor. So far I'm really happy with it. Sportsman's and Cliff's carry ammo, although it seems to fly off the shelf fairly quickly. They both have brass too. I'm thinking that Cabela's will be carrying it in the future.
As for brass, I've been happy with the newer runs from Hornady. The older runs they were doing something that made the brass a bit soft (I remember reading an article on it somewhere), but the newer stuff seems to be good.
Lapua is now making brass for the .260 as well as the 6.5x47.
One nice thing about the 6.5CM is the match grade ammo from Hornady is cheap, although sometimes it is hard to find locally.
After shooting .308 for years, the 6.5 is just better all the way around. Longer range, better BC bullets, better against the wind, etc.
In a bolt gun, any of the 6.5's (6.5CM, .260 and 6.5x47L) are great. In a semi-auto, I wouldn't bother, because they don't really give much more advantage over a .308.