Effect (in theory)
3 in One: 3 quarters are shown Stacked and spread slightly apart so that a small crescent each of the coins (except the top) shows. Drop it on the table/hands or close your hands and one vanishes.
Butter coin: Same as above except with half dollars, and it is easier for the spectators to tell that there are 3 coins. The crescent is larger.
Flipper coin: 3 coins are clearly shown, spread pretty far apart. Spectators should look from a distance though since the illusion of 3 coins isn’t perfect since one coin may seem smaller and edgeless.

Method (ease of use)
3 in One: Can use borrowed coins (everyone has quarters), and is very easy to “load” up the gimmick. Some may find it easier to palm since it’s smaller. Gimmicked coin looks VERY nicely made, crack is invisible even to yourself, however as with most folding coins the rubber band on the side gives it away the most.
Butter coin: Can’t really use borrowed coins (not too many people carry half dollars), and is also very easy “load” up. Some may find it easier to palm since it’s bigger. For most people, the gimmick coin looks good on the front, but is crack is more obvious on the back (though most people won’t care). Some people (like me) have gotten defective coins, that look bad front and back. Rubber band on side is a giveaway. The coin is a too loose.
Flipper coin: Hard to load up (really hard compared to 3 in one and butter coin), and the Sasco flipper coin is badly made in my opinion (looks very bad). Hard to repair and maintain. Doesn’t have the rubber band problem.


Routines:
3 in one: No routine for using it as a flipper is included.
Butter coin: 6 very nice routines.
Flipper coin: Bad routine.

Conclusion:

I would go with either the Butter coin, or the 3 in one if you’re creative. The butter coin, though it seems like it costs a lot, is worth it (if you get a normal good coin) since it comes with a DVD with great ideas and routines, and uses half dollars, which are easier to see. The 3 in one is great in that its cheap, and very nicely made.


Next: Bite out Comparison : 3 in One, Buttercoin, Folding Half

I agree I love the 3 in 1