The busiest domain registrar (GoDaddy) on the web is designed the worst? They 1) flood you with choices (left hand nav, topnav, every page with a dozen dropdowns), 2) cross sell too much (hosting, privacy, 5yrs, 3yrs, .net, .info... just way too many), 3) every page in checkout process has more than one submit buttons!
But one thing I don't complain about is, its inexpensive!