I am, they seem like a great idea and I wish they were common in my part of the world.
But they only motivate manufacturers' packaging choices in the rare case where it's more cost effective to recycle the material than to purchase it new. If it's cheaper to use something that ends up in a landfill, most companies just will.
I think we need something that motivates them to want it back no matter what it's made out of.
---
I make beer and I've been reusing the same bottles for years. The trick is to rinse them right away, otherwise it's a pain to get the dried beer gunk off the bottom. Bottle return programs don't motivate users to clean the bottles, so they need to be recycled rather than merely sanitized and reused (I think).