IMLT 2013 and IM Boulder 2014 is an interesting comparison... in a lot of ways they are similar and a lot they're opposite. I ended up with similar times for both races, and here is the direct comparison. The swim at Boulder was beautiful and uneventful. The swim at LT was brutally cold, offered poor visibility, and the infamous changing tent. The bike at Boulder was challenging but fast. I biked similar wattages and was 50 minutes faster at Boulder. The run at LT was cool, pleasant, and relatively fast. The run at Boulder was a freeking death march. Looking at the weather reports doesn't even come close to telling the whole story. Carnage from mile 0 with people caked with salt, yacking all over the place, and being carted off the course with med staff. I've done 12 and it was by far the hardest marathon. I talked to someone that has done 40 including winning his age group at Kona several times and he also said it was the hardest marathon he'd ever done. Tahoe will always be a very hard race but Boulder could be smokin' fast with mild weather.