A word of caution, make sure the restaurant you book is actually a restaurant that is at Disney Springs. The one time I've used OpenTable to help with Disney reservations, I found a Mexican-style restaurant in the DS area for our party of nine on our arrival day. I was impressed that the typical menu pricing seemed reasonable (for Disney standards), which should have been my first clue.
When we arrived at DS to find our restaurant, I realized the place wasn't even at DS and was located a good 2 miles away or so. Big whoops! We managed to get a walkup at Planet Hollywood, but it made for a pretty stressful start to our trip.