One benefit of this to founders is that a M&A deal provides instant liquidity (barring earn outs), whereas an IPO largely prohibits you from selling off a large percentage of your stock.

Yeah. The founder of one of our vendors sold his company for eight figures recently. His only obligation after the sale was to stay on for six months (at an exorbitant salary) while the management structure was integrated into the new parent company.

Seems like an IPO is riddled with all sorts of waiting periods and notifications and paperwork people will want to sue you over if they lose money. I'd definitely go the buyout route if the price was right.