It's easy as a tax matter to go from LLC to S corp, hard to go back (as it is a taxable liquidation). Some LLC's do go to the trouble to be taxed as an S but my advice is always to conform the corporate reality to the tax fiction and incorporate first because it is very easy to blow the second class of stock rule with an LLC structure if you ever get additional partners or members.
1 lawyer agreed with this answer
This is why closely held corporatiosn should have buy sell agrements with dispute resolution clauses. Absent that, unless someone has enough shares to blow up the company, you are married to your other shareholders. having said that, there are usually strategies designed to force a resolution short of litigation depending on your particular metrics.