You are right and wrong about winning ultras. You are right in that just winning an ultra doesn\'t mean much; just like road races of all distances, there are plenty of relatively non-competitive races out there. You are wrong in your assertion that outside of the US 100k and 24hr championships, there are no prestigious ultras. As the most obvious example, Western States attracts a deeper and more competitive field than either of the two races you mentioned. The JFK 50-mile, Leadville 100, Angeles Crest 100, White River 50 mile, and probably numerous other races often have deeper fields than the US 100k and 24hr. I would say that in general, as far as the US ultra scene goes, trail races and especially 100 mile trail races are where most of the top competitors go. As far as your assertion that most 2:25 marathoners could \"eat up\" the top ultrarunners in the US, all I can say is, you\'re wrong, and I\'m curious where you get your info about ultras--sounds to me like you\'ve picked up a few scraps of info and jumped to your own conclusions without any firsthand experience. Personally I\'ve participated in quite a few and have witnessed numerous 2:25 and faster marathoners get beaten by guys with significantly slower PR\'s. Tough terrain is a great equalizer. Don\'t get fooled by looking at overall pace and thinking \"how hard can 10 minute miles be?\"
Still, I will wholeheartedly agree that \"winning an ultra\" isn\'t one of the 10 most difficult things to do in sports.