A clever idea. A passionate founder. A little bit of well-timed luck. What makes for a great start-up? The July cover story of Inc. raises that questions and invites readers to weigh in. The article, which was assembled by writers Stephanie Clifford, Max Chafkin, Sarah Goldstein, and yours truly, takes a look at four fledgling ventures. Each company is examined on qualities ranging from the size of the market for its product to the competition to the capital it has raised so far. Then, we asked legendary entrepreneurs—Roxanne Quimby of Burt's Bees, Paul Orfalea of Kinko's, Gordon Segal of Crate and Barrel, and Tim Gill of Quark—to provide feedback to one of the start-up companies. (To read a brief introduction to the package, click here.)

Company #1 is Nanda Home, a one-woman design company founded by Garui Nanda, an accidental entrepreneur—an MIT grad student who discovered surprising consumer demand for one of her school projects, a $50 runaway alarm clock. After only two months in business, Nanda was at breakeven, and ready to contemplate life as a business owner. To read her profile, click here.

Company #2 is TechShop, a membership-based inventor's workshop in Silicon Valley. Tinkerers and hobbyists can go there to learn new skills, such as how to use a lathe, or to create and refine prototypes. The company hopes to expand to new markets shortly, and makes good money selling materials and other extra products to its members, whose monthly fees help cover the cost of overhead. To read more about TechShop, click here.

Company #3 is Ventana Health, the maker of Zsweet, a sugar substitute that is not artificial and that has no calories. Founder Tim Avila took his idea to several large food companies before striking out on his own. The company, based in Los Angeles, got a lucky break when Whole Foods cold called them (seriously!) to pitch a distribution deal. Avila is particularly eager to tap the market of people with diabetes and the Latino community. To read up on Zsweet, click here.

Finally, Company #4 is GreenPrint, a software firm in Oregon. The company's technology promises to cut down on printer waste, helping both companies and individuals save money and trees at the same time. Among other deals, GreenPrint hopes to gain distribution through a major office super store. It is also in talks with an international financial institution. Either deal would give the company access to an influential installed base. To read the GreenPrint profile, click here.

Now it's your turn: which company do you think has the best chance of success? Is there a company here that you believe is destined to fail? And what do you think of the feedback offered by the entrepreneurial legends? Post your thoughts here or send them to mail@inc.com.

Finally, do you have a cool start-up in the works? If so, let us know by sending an e-mail to mail@inc.com.