@ Fiorite- The biggest benefits of the partnership and sole proprietorship have to do with taxation, cost, and control.
Forming an LLC can be costly for an individual or a few partners looking to start a small business. A sole proprietor or a group of partners also avoids the dual taxation that an LLC or corporation is subject to. Corporations have to pay taxes as its own entity, then every investor pays taxes on his or her share of the dividends. Finally, those in sole proprietorships and small partnerships often have more control over the day-to-day operations of their business than a corporation or a group of limited liability investors.