The best "bought" burgers that I have had come from Di Lillo's in the Montreal area. They use a mixture of beef, pork, and possibly lamb??? They virtually deep fry the meat in it's own fat so it is very juicy. They are served upside down in a paper wrapper.
I also had a good burger and excellent onion rings in Hawaii. I am not sure about the name of the restaurant but I think it was Bubba's and their slogan was "We only cheat drunks, tourists, and attorneys".
Sorry Bernie but I gave up on McD's burgers many years ago. They do have a decent breakfast however. Of the chains, Wendy's have the best burgers. There is a Canadian chain called Harvey's that used to have fairly good burgers but they have gone down hill probably due to cost cutting to remain competitive with the bigger chains.
Wayne