Definitely prune juice...
Can't remember last time I has some but, I did like them. Not in juice form or any other form actually. Just plain.
Now spinach...pooey,fffahh,frakin. I can't even handle the smell. If my life depended on my eating that,,,,, I don't know. 
Personally I can't wait to just take one pill for the day, and all your vitamins, nutrients,etc. are takin care of. No hunger. Now that's performance.
Wouldn't you say?