They offer a decent option particularly if you are planning to visit the Aqua Park in Calis.
We visited these in May and they had a deal whereby for every 50YTL you spent you recieved a voucher for adult entry (25YTL) into the waterpark.
To be honest I think the prices were on a par with the rest but as we don't eat out much cannot compare the quality of the food with that of other restaurants but we were happy with what we ate and will be using the voucher when we visit in July.
I'm not sure whether this is an ongoing offer so it may be worth asking before you go in.
Hope this helps
Gav
