Can someone in layman's terms briefly tell me why a small business would be set up as a S-Corp versus a regular corp?

No corporate level taxation. The income is reported at the shareholder level. Example: C-Corp has $100 of income. Pays $34 tax. Distributes a $66 dividend to shareholder. Shareholder pays $24 tax. Shareholder ends up with $42. S-Corp has $100 of income. Pays no taxs. Reports the $100 to shareholder. Shareholder pays $36 tax. Shareholder ends up with $64. Of course, it is much more complex than this. But that will give you the basic idea.

In addition, losses can be passed through to the shareholders' personal returns. Many corporations start as S corporations to deduct losses in the early years and become C corporations when they are retaining income to fund expansion.

Thanks to you both.