I have put 25,000 miles on my RT in 3 years. I have ridden it in temperatures from 30F to 117F, in blistering sun, rain, and snow.
It does get a bit uncomfortable when the temperature gets above 85F, but below 50 in rain or snow, I can't think of a better fairing to get behind.
I have ridden through heavy rain for over 300 miles and not gotten soaked. Been comfortable riding 10 hours through snow flurries. Yes there isn't enough knee room, but the protection from wind and water is great. You need waterproof boots, and good socks because your feet are out there in the open, though.