Reporting back now...I went with Willow Leaf White. What a great butter bean!!! I did space them further apart than my snap beans, but I only went to about 8 inches apart. They did great. Got lots of sun and because of the narrow leaves on this variety, I can easily see all the pods when picking. They shelled pretty easily and taste great. We ate the first of them tonight. Mine went in a bit late because I was waiting for my sugar snap peas to finish up. I doubt I'll even bother to grow another variety now, we are so happy with the Willow Leaf. Thanks for everyone's suggestions!