While Twitter's (TWTR) IPO seemed like smooth sailing compared to last year's Facebook (META 1.95%) debacle, Facebook's IPO was actually a bigger success. In this story from Investor Beat, Motley Fool analysts Morgan Housel and David Hanson explain why Twitter should be slightly ticked off with underwriter Goldman Sachs (GS 1.41%). They also share which IPO from the class of 2013 is the best long-term buy for investors.