Investors in BJ's Restaurants (NASDAQ:BJRI) must have felt good when its share price moved up substantially from around $8 per share at the end of 2008 to more than $54 per share in 2012. However, after that significant rise BJ's had plunged to around $27 per share at the time of writing. Despite the drop, BJ's still has a high forward earnings valuation of nearly 26.7. Investors might be scared of that high valuation, but it is nothing compared to the valuations of Chipotle Mexican Grill (NYSE:CMG) or Potbelly (NASDAQ:PBPB). While Chipotle possesses a forward earnings valuation of 40.5, the forward P/E of Potbelly is even higher at 69.6. 

The market has lost appetite for BJ's
BJ's is a contemporary, full-service casual-dining restaurant chain that operates around 140 units with an average unit volume of $5.8 million. The company has a track record of annual double-digit capacity growth with the potential to increase its restaurant count to more than 400.

Part of the reason why the market lost its appetite for BJ's was its sluggish comparable restaurant sales. While BJ's experienced a tiny increase of 0.03% in comparable restaurant sales in the second quarter, its comparable restaurant sales decreased 2.2% in the third quarter. On a two-year cumulative basis, BJ's delivered no growth in its comparable restaurant sales.

The company plans to have less focus on new menu development. Instead, it will focus on refining its menu and kitchen operations to drive its capacity over the long run. In the next year, BJ's estimates that it will open 17-19 restaurants. 

Chipotle keeps growing
The market always expects a high growth rate for Chipotle. In its third quarter, the company reported an 18% year-over-year increase in revenue, and its comparable restaurant sales surged by 6.2%. The bottom line experienced quite a sweet growth rate too, at 17.2%, to reach $2.66 per share. By September 2013, Chipotle had around 1,350 restaurants in total, focusing mainly in the U.S. market.

However, the growth story of Chipotle does not stop there. There are tremendous opportunities abroad for growth. In the third quarter, Chipotle opened its first Chipotle in Frankfurt, Germany, bringing its total international restaurant count to 14. Furthermore, Chipotle is diversifying its product offer to consumers. With the same store format, Chipotle has begun to provide consumers with dishes from Thailand, Singapore, Malaysia, and Vietnam via its ShopHouse Southeast Asian Kitchen.

ShopHouse expects to fit consumers' increasingly healthier eating habits with gluten-free and dairy-free menu items. Chipotle has three ShopHouse restaurants already, and expects to open several more in the Washington D.C. and Los Angeles areas in the next twelve months. 

Potbelly will pay its previous investors $49.9 million in dividends
Potbelly focuses its food offering on sandwiches, with the passion to be "the best place for lunch." Since 1997, the companies total restaurant count has advanced dramatically, from only two to as many as 300 in 2013. The company plans to increase its restaurant count by 10% annually.

What investors should notice is that Potbelly raised $105 million from its IPO, but not all of this cash will be used for business expansion. In its S-1 filing, the company stated that it intended to use the net proceeds from the IPO to pay a previously-declared cash dividend in the total amount of $49.9 million. Thus, only $55.1 million will be used to either repay borrowings under its credit facility or fund its operations. 

My Foolish take
Among the three, I still like Chipotle the most because of its growing operating performance, potential for international expansion, and its new ShopHouse model. BJ's is cheaper than Chipotle, but it is cheap for a reason: declining comparable restaurant sales. Potbelly, at nearly 70 times its forward earnings valuation and with no dividend payment for new shareholders, is a bit too expensive at its current trading price.