Yep, done it lots of times! Juice is a lot more work than the Master-Cleanse -- you shop, wash, purify, prep and juice fresh fruits and veggies every day. However, it is VERY supportive nutritionally, very cleansing and a good option for the long haul.
However, I don't know where you got that people lose more weight on juice. On any fast, you tend to lose about a pound a day, about half of which returns when you cease fasting. You can minimize regain by shifting right into a good, nourishing, clean diet and exercise program. The math is simple: if you take in more calories than you burn, you gain.