Consistency will always be on Starbucks' side. It is hard to mess up something as simple as an Iced Coffee with no sweetener or milk. Maybe it is best to keep it as basic as possible.
The drive thru moves at a quick pace and I can easily get my order in and ready within minutes. If I do not have time to just sit back and enjoy the ambiance than Starbucks is good. If you don't have to be anywhere, go to one of the local own shops and just enjoy the atmosphere.