A C Corporation is a for- profit, state- incorporated business. Some benefits of a C Corporation are that it is easier to raise capital as a corporation than as a sole proprietorship or partnership. If a stockholder dies or wishes to sell out, the corporation still continues. They also utilize health plans and better retirement options like 100 percent deductable health insurance. Some disadvantages of a C Corporation is double taxation, formalities and regulations must be followed much more closely there, it is costlier to start than other businesses, and it takes more time and effort to maintain.
Link: http://www.allbusiness.com/business-planning/business-structures-corporations/2515-1.html
An S Corporation is a business that has shareholders and is taxed like a sole proprietorship or a partnership whereas a C Corporation is taxed as a seperate business entity. Some benefits of an S Corporation are that you can have the protection of limited personal liability without having to pay corporate taxes, and also you can minimize self-employment tax. Some disadvantages are that a lot of regulations and requirements must be upheld by an S Corporation, including a limit on the number of shareholders and like a C Corporation, it can be costly to set up and start up rather than starting a sole proprietorship or a partnership.
Link: http://www.allbusiness.com/business-planning/business-structures-corporations/2516-1.html
An LLC is a Limited Liability Company. Some advantages of an LLC are that the members are afforded limited liability and have pass-through taxes similar to a partnership, and you get all the benefits of forming a corporation but you avoid a few drawbacks that you would run into if you formed a corporation. Some disadvantages of an LLC are that businesses that operate in more than one state may not receive consistent treatment, some states do not tax partnerships but do tax LLC's, and an LLC is treated as a partnership cannot take advantage of incentive stock options.
Link: http://www.limitedliabilitycompanycenter.com/llc_disadvantages.html
And: http://www.gaebler.com/LLC-Advantages.htm
