Up modesty following yesterday's earnings release, Panera Bread Co. (NASDAQ:PNRA) plunged more than 9% to close down at $42.09 after its conference call. The stock, which had climbed some 10% since the company reported strong same-store sales last week, headed south when management acknowledged that the popularity of low-carb diets would bite into sales growth.

I have mixed feelings on this one.

Panera is one of America's favorite shorts with about 30% of its float borrowed and sold by investors betting it heads lower. At more than 30 times next year's earnings the stock's valued like a Starbucks (NASDAQ:SBUX) or a Krispy Kreme (NYSE:KKD). And unlike Starbucks, Panera is dependent on new store openings for its 30% or so growth; its same-store sales picture just isn't that pretty.

You see, where same-store sales over the past year were up between 2% and 2.4% at company-owned bakery-cafes, they were down 2.5% to 3% at franchise stores. That point becomes critical when you consider that franchise stores account for almost three-quarters of Panera's 558 bakery-cafes.

But where Matt Richey argues, "Panera's bakery-cafes don't have the distinguishing qualities of a Starbucks or a Krispy Kreme," I disagree.

Panera's bakery-cafes offer unique, reasonably priced products that cater to a more health-conscious crowd. With its sandwiches and sourdough bread bowl soups, Panera offers quiet places with good food and wireless Internet connections. That's food you can't get at Starbucks, and it's healthier than a Krispy Kreme donut.

The company also has an identifiable brand, at least out here in St. Louis where it's based. The local bakery-cafes -- named St. Louis Bread Co. -- are exceptionally popular with the college crowd or anybody looking to get work done.

In fact, I'm sitting here now with my French onion soup in a sourdough bread bowl, Frontega Chicken sandwich, and an iced green tea.

Bottom line: From what I've seen, Panera's got too good a product to short the stock. But the story is the same as it was last year: Panera's still got too high a price and enough baggage to keep me from going long.

Jeff Hwang owns shares of Starbucks, and can be reached at JHwang@fool.com.