I just finished doing the Benton Mackaye/AT loop + 100miles(650 miles total). I used a 27Liter pack, Poncho tarp, bivy, 3/4 CCF, base was under 4. No stove or anything else I didn't need. I only used two 20oz bottles for water. I was pushing 20-25miles, so it worked pretty good for my trip.
Overall the hike went well but I highly doubt I'll ever go SUL for a long distance hike again. My main problem was it's hard to carry enough food & I started to miss hot drinks. Not having coffee, tea & cocoa with me hurt my moral. I didn't care about cooking a meal, but no drinks was really a bummer.
I usually eat 2.5 - 3 pounds of food in the summer after two weeks. If its colder I'll easily carry an average of 4 pounds a day in food/drinks. I just missed having the choice of being able to bring along whatever I wanted food wise. I'll bring along a dozen donuts and two pounds of bread, fruit, eggs, ect with me if it looks tasty in the store. With such a small pack I had to strategically plan out my food and had to really look at the calorie to ounce ratio.
It's not really hard to plan out a SUL hike on a spreadsheet, but doing it and limiting yourself is hard. The only reason I could see myself doing another SUL long distance hike is if I'm on a time constraint or if I'm doing some type of fastpacking.