I have always made hamburgers from scratch, but decided to try some of the preformed patties from the supermarket freezer case. It was just to have some easy convenience food on hand. After reading the labels I got some Husken (sp?) brand burgers with onions embedded in them. Less fat in those.
You know, they're pretty good. If they were restaurant burgers I'd say they were very good. They do have a "processed food" flavor, but it is slight. I may just keep a few on hand for days when I want an easy meal.
I just take them out of the individual plastic wrap and toss them on the grill.