I used the SFG method this past year for the first time and loved it. Got carried away with some of it and caused some of my onions to become too shaded by tomatoes on a trellis.
I will be repeating the SFG method this year, especially with my sweet onions, lettuce beds, mangels, etc. I have a pretty roomy garden but I want to pack in the veggies to produce more and to eliminate spaces that weeds normally would grow.
I'm not strict with it, except in my cold frame, but it has awakened me to the fact that all those years with traditional row gardening that I was wasting soooooo much space.