Regarding AA, Chana what you said is true as long as the DBV is not less than the price of the tkt. If its less than the tkt price then you do end up paying the taxes. If its more then the tkt price then you do get back the difference but will be paying that $5/10 each time you use it.

I personaly received over $3000 in DBVs from CO last yr and have been able to use all of them so far, and Im not complaining. I love being able to tkt it online rather then having to mail it in or be hassled and go to an airport counter/CTO.