Probably the best thing to do is just compare package prices. When we booked our last trip in December the price for the Costco package with a "free" character meal was exactly the same price as the AAA package with vouchers for a premium character dining at Goofy's Kitchen. As previously stated, both of these travel companies book through WDTC so I don't know that there would be a huge price difference, you just have to compare. We did book through AAA because we worked with a Disney knowledgeable TA, and we were happy with our experience. Our TA also made our dining reservations for us, which was nice because it was over Christmas and very competitive. We did like the Diamond card that came with our package which gives you discounts to DTD restaurants, and I know we used the free kids meal at Rainforest Cafe (unfortuately I threw the card away and don't remember what else was included). You also get preferred seating to some of the shows, Aladdin being most helpful, and tickets to TTMM. I was also told they will lower the price of your package to match the current special, which is a WDTC policy I believe, so if a summer discount surfaces it could lower the price of your reserved package (fingers crossed!). I would probably not be very comfortable working with a TA who was less experienced with Disney.