I have both and both of them are great. I can't say which one is better because it depends on who I am performing for. Alot of times I end with fallen because you tells them what really happen, instead of the card going up, the deck
melts down and they can see that happening.
Shifty isnt bad at all but it is really knacky. But again people can see that is traveling up.
Personal taste, do you want the deck to melt down on the card or do you want a card to travel up?
This is my review of shifty and my review on fallen can be seen
Here
Cheers
Andrew