Well, from what I understand, if you're likely to get into any Epcot restaurant on short notice, this is one of the few you might be successful with. We managed to get an ADR 2 nights before we ate there with no problem, but I'd still try to book an ADR if you can.
The food and atmosphere were fantastic, IMHO. This is my favorite restaurant at WDW so far, I think. LOVED everything.. the musicians, the serving staff, food, drinks, bellydancer! All great.