In a decade and over 100k miles of professional riding, with many of my days starting out in a thunderstorm, I have yet to find a boot where waterproof and comfortable on a warm day co-exist. For that matter, I haven't found rain gear that will do it either. Some are better than others, but the most practical for me has always been the rubber slip overs for whatever boot I happen to be wearing for the weather conditions. Rainy and 40 and rainy and 80 are two different worlds when you are spending hour after hour in the saddle.
Good luck with your search and I would be interested in seeing what kind of test period people have had when they give their responses. Anything is doable for an hour or two in moderate rain once or twice a year.
2006 Vegas 8 Ball
2014 Harley FLHTP (Keeping service techs busy)