The upside of electing to be an S corporation is simplicity. The corporation is you and you are the corporation.
The downside of electing to be an S corporation is that, by extension, YOUR FAMILY is the corporation and the corporation is YOUR FAMILY if you file a joint tax return. Also, with an S corporation you can't decide to pay yourself a stock dividend, or a cash dividend on your stock, instead of a wage, as a way to reduce your tax rate.