viking499:
As you probably already know, the 6.5x55 is not a high intensity cartridge and tends to work best within its conservative design parameters.I have used Winchester, Remington and Norma brass for my CZ550 in 6.5x55 with no complaints about any of it.
Norma seems to be more consistent. (I weighed 100 cases of each after sizing, trimming and primer pocket uniforming.)
However, Remington appeared heaviest of the three, indicating smaller internal capacity.
Winchester weighed the least (not by much). It seemed to be thinner and a little stiffer, too.
None of the above have been fired enough to require discarding, and the most any have been fired is 4 times. I keep the loads fairly mild, too.
Really, to answer your question: If you keep your loading charges within a relatively conservative spectrum, the brand of case will make little difference. If you will be loading toward the high end and are shooting long range or benchrest competitions, then you may want to splurge for the Norma or Lapua.
FWIW, I have found Remington and Winchester to be perfectly capable of satisfying my needs without the additional expense of Norma. Your loading technique will likely be more important than your brand of brass.
I hope this is helpful.
Poper