I posted the same thread a while back. We are going in Sept and I still have both booked. However, after reading everything, I will definitely do the HDDR. I can't find anyone to say anything bad about it. I think the food is a little different.
The reviews on the Backyard BBQ differ. Some are raving, others say it is chaotic. I think the open area and characters would be great for my very active kids, but if it is hard to keep up with them my DH and I will be nervous wrecks trying not to lose them in the crowd.
I think that I have decided to do HDDR and then just stick with character meals for dinner for the character interaction, but this is partly because of the logistics. The Backyard BBQ is only offered on Tues. and Thurs. and we want to do Spectro on Tuesday night and then on Thurs. we will be at the Yacht Club so we will have to do a lot of travelling. I still haven't cancelled though, because some replies said the Backyard BBQ was a better deal than HDDR and that young kids enjoy it more.