Just thought I'd share my experience after my visit last december. While I agree that service could be better for an 'upscale' restaurant (compared to restaurants outside the parc...), I found the service still more then adequate. Me and my girlfriend had booked a table for lunch about an hour in advance. We arrived as one of the first and were seated at a table with a view over Main Street. I can certainly recommend this to any other couple as these tables are situated away from group tables, providing for a very calm atmosphere with a great view over Main street. We both had the starter + main course menu at 28.99 together with a bottle of white wine. We went for the starter with goat cheese and the Cod in a spicy crust as main course. I must say that overal we were very satisfied with the quality and the taste of the food.
While a restaurant like this may be a bit to pricey to have all of your meals hear during your stay, I personally find this kind of a meal to be of greater value then any of the fish and chips or burgers offered in the parcs. The burgers and fish and chips type of food usually sets you back 10-15 euros for something you could have for half the price in a regular fast food restaurant. But finding a dining experience like Walts or Blue Lagoon anywhere else below (or even at) this price point will be a lot harder. This is just my opinion, and Walts and Blue Lagoon are the only table service restaurants in the parcs that I have tried out so far.