Which Beco retailer has the best return policy / customer service?

Almost all retailers have good return policies (15-30 days) and won't charge restocking fees as long as you comply with their return conditions. Basically, carriers need to be like-new so they can be resold if it doesn't work out for you. So if you've washed it, or there's pet hair or baby spitup all over it, or it reeks of smoke, you'd probably get charged a restocking fee because then it can't be sold as new.

I would recommend Along for the Ride -- great customer service and quick shipping. She is about to have a baby, but I know she's trained her dh on shipping, so that shouldn't be a problem!

You can find all the distributors on the Beco website and then just check their policies.