Mainly taxes. Inc. provides better tax breaks. Even we as individuals, can inc. and save if you want to go though all the paper work. A limited liability company is limited but does have some advatages
no limit on the number of owners, profit and loss are passed through to the owners' individual tax returns,
no annual meeting or minute book requirements.
Inc advantage,
may issue shares of stock to attract investors, corporate income splitting may help lower overall tax liability.