In Chicago, you have Mario's Italian Ice on Taylor Street. Joe's in Tempe, AZ gives them a serious run for the money. The flavors here remind me of Mario's back in Chicago. However, I encourage you to be adventurous and try some of the others. Sure, they may have some wacky names but the flavors definitely are serious. The lemon is one of their "normal" flavors which has just the right amount of tartness to complement flavors such as Watermelon, Strawberry Lemonade, Blue Hawaii, and even Wild Cherry.
The service I receive here is consistent with their quality. I have never had a bad experience here.