I have a trainer, but I hate using it. For one, the workout never varies. Second, you have to change your tire and skewer, or your entire back wheel, when going between trainer and road. I would have guessed that pros would use rollers rather than trainers, as they're more challenging, but I don't actually know for certain. Anyway, being able to have adjustable courses with real incline/decline, plus wind resistance, seems like an added feature worth paying for. Although I'm not sure it's worth paying $1200 for!