FIND_teamMore importantly to some:
1. Tiles are in back-order until at least Summer 2014.
2. The Find has a replaceable battery and thus has an indefinite life. In contrast, with the Tile, they deactivate them after a year of use, so you are required to purchase wholly new Tiles to replace all of your year-old ones every year.
Both have their merits, but it's that latter point that makes the biggest difference to me.