Oh man I have several sandwich effects, I can't decide which one to use primarily, I like all of them, 3 plus 2 created ones, but I don't like performing them together... Dilemma!
Anyway, they are:
Dirty Stinkin' Ape in the Middle, from Tyler Wilson's book Dominatricks. Pros - Clever, very clean, natural misdirection only one fairly easy move needed. Cons - Provided patter can be a little corny/inadequate imo. Generally my workhorse, the one I perform most.
A Simple Sandwich, from Aaron Fisher's book The Paper Engine. Pros - Uses only one sleight, simple construction, solid and tight routine in every action, invisible. Cons - That one move is fairly hard. Doesn't appear as visual/impossible as the other two imo. I perform this less but it's very solid. With Gravity Half-Pass down it's also invisible, no-one can tell something happened.
Half-Vanish, from Daniel Madison's Dangerous Vol. I - Mystique. Pros - Creative routine, moat visual of the three, incorporates a nice vanish. Cons - Most complicated of the three to perform, harder to get perfect and it'll be obvious if it's not perfect. I'm still practicing it but it'd be more suitable for energetic small groups if you've got them on side.
Another one on the same DVD is Catch - I don't like it and don't use it, I don't like the flourishy style combined with magic, and even the DVD performance is hesitant and sus imo.
I like all three for different reasons and perform them in different situations. Hope this gives you a few more leads..