Just a bragging point: I've totally been to the original Heidi's Brooklyn Deli in Denver, Colorado. Its Peoria counterpart is a fantastic place to get lunch in the West Valley.
I have sampled quite a few of the menu items. I do tend to stay away from anything with mustard, ham, bologna type meats, and rye bread. However, the meatball on Italian bread and the chicken marinara on French bread are delicious menu options. I also like the Club sandwich on the croissant. They also have a "build your own" option if nothing on the menu looks appealing (an impossible feat). Every sandwich comes with a bag of chips and a pickle.
The milkshakes and malts are made from real ice cream (also available by the scoop) with generous portions. All of the desserts are fabulous, but they advertise the cheesecake as "homemade" and I'm pretty sure it is not.
Heidi's also serves breakfast, but I've never gotten around to trying it. I would love to sample their lox bagel because it looks out of this world.
The prices are more than reasonable for the portion sizes and quality that Heidi's offers! My only complaint is that the restaurant keeps odd hours. It seems like they are never open when I get a sandwich craving!