We did the Dine with Shamu a year and a half ago. The show was great but the food was a terrible buffet set up in a small crowded stuffy room with a long line. Everything was cold and tasted prefab compared to any Disney restaurants. We were tired and hot, and ds was only two and free, so the food wasn't that big of a deal to us. The show was worth it though.
We haven't tried the Shark Encounter Restaurant, but I think the counter service has really gone down hill. Very slow and expensive with rude servers, again, I don't think it even comes close to comparing to WDW.
Hope this helps.