I'm not going to be going, but one of my partners is.
DMA is very similar to ERA (retailing.org) but its a bigger show. If you're only into the affiliate side of internet marketing, then I don't think these are good shows for you. However, if you own your own products, represent an affiliate network, are a service provider, then it might be worth the trip.
It will however be a very different crowd from Ad-Tech, Affiliate Summit, ASE, etc.