I've got the CZ 550 FS in 6.5x55. Read my review here: http://www.hunting.net/forum/tm.aspx?m=2530213
Since the review, I've put a couple of hundred rounds through it, mostly using military surplus ammo 139 grain and Prvi Partizan 140 grain SP.
I love the gun! It shoots well, fits me like a glove and looks great! I am still working on tightening my groups, at 100 yards that's quite a job using iron sights (I can barely make out the target at 100 yards
The more I shoot the 6.5x55 the more I wonder why this caliper hasn't caught on more here in US. In Scandinavia this caliper is used for everything from big bird to moose successfully. It has a low recoil, I can shoot easily a hundred rounds without any problems. My previous rifle was a 30-06 and that thing kicked so hard you did not want to target practice for long. I firmly believe that a low recoil helps me hitting my targets accurately. This caliper would be great for a young starting shooter due to the low recoil.
Regarding ammo, I've been buying them online. Samco has surplus stuff for 37 cents/round and you can buy Prvi for 65 cents/round at Grafs. The premium hunting rounds will cost you over $1/round, but how many do you need over a season? The local stores here in GA don't carry much of the 6.5x55, but I don't see that as an issue as I can get ammo over the Internet. I don't handload, but the 6.5x55 seems to be a popular handloading caliper.
If you search 6.5x55 you will find out that there is a lot of people who just flatly love this cartridge. I've yet to come across one who would say it's not adequate for the most common prey here in US, the whitetail deer.
Ditto for CZ 550. It's an accurate gun and a good value for the money, IMHO. Hope this was of help.