Tried the Grand Mac over the weekend and it was pretty awesome, but it definitely walks that "too much bun" line. I wouldn't recommend eating it without sauce or it'll be too dry.
I don't like Mac sauce so I swapped it with ketchup.
Best part was how overly perfect they made it compared to when I usually order at that location. Maybe they forgot how to make big Macs and ordering my GM caused them to go look it up and do it slowly?