Murray used to be a seperate company, but Siemens bought them and has continued with the name. They are the exact same breaker.

I know SQ D QO is suposed to be the best, but I personally wouldn't pay the diference. My main supply house carries Cutler Hammer and has us on a rebate price set up that makes Cutler Hammer CH the brand we use. It would cost me at least $150 more to use SQ D QO for a 200 amp panel and breakers. Cutler Hammer CH is a great line and better than most, so that's what I'd use.

For your service change, you might want to see what brand the EC wants to use. If he/she isn't set up for SQ D, you will pay a lot more. I would have to charge more for even GE or Siemens than I would for CH, because of special pricing.