Having been to Winnipeg in November, I can understand Machka's sentiment. The answer depends on where you ride. Here in NC, for me, general road time is much easier on the heart than on my trainer or rollers. The worst thing I have to worry about on the rollers, however, is falling over sideways and looking like an idiot. On the road, I am sure my heart rate goes up at least 5 bpm due to cars getting a bit too close for my liking.