Today, shares of Cosi(Nasdaq: COSI) made their debut on the Nasdaq. Last night, underwriter William Blair priced the shares at $7, allowing Cosi to raise $38.9 million. As of 2:00 p.m., the shares were up nearly 13%, trading at $7.90.

The creative New York-based restaurant concept is an interesting mix of coffee hangout, sandwich shop, dessert parlor, and late-night bar. Those who've visited one of Cosi's 79 locations, concentrated on the East Coast, can testify to Cosi's great food and inviting atmosphere. Imagine the coffee shop in Friends, but with mood lighting and an extensive menu.

Restaurants are rarely good investments because of intense competition and high capital costs for expansion -- but Cosi has enough differentiation to make it worth a Fool's attention.

Here's a quick rundown of the company's financial position:

On a post-IPO basis, Cosi has 16.6 million shares, which at $7 yields a market cap of $116 million. With trailing annual sales of $78.7 million, it has a price-to-sales ratio of 1.47. That may look cheap compared to Panera Bread(Nasdaq: PNRA), which trades for 3.8 times sales, but it's expensive compared to the industry's average price-to-sales multiple of 0.4. Plus, Cosi isn't yet profitable. Currently, it is burning about $3 million from operations per quarter. In all likelihood, it is about a year away from profitability.

Back in 1998, Panera was in a similar position in its growth curve and still spilling red ink. But through store expansion over the past three years, Panera has become profitable, and since then the stock has appreciated tenfold. Could Cosi do the same? Yes, but I'd take a wait-and-see approach to this business.

A weakening U.S. consumer doesn't bode well for restaurants in general. Also, after six months, insiders will be filing to sell some of their Cosi shares, which could weigh on the stock. In addition, from a fundamental perspective, I'd wait for Cosi to generate positive cash flow from operations before giving the stock any further consideration. That's probably at least a year away, during which time a Fool can better get to know management and follow its ability to execute its growth plans.