I have both. I first picked up a trainer, Cycleops fluid model. I used it for a winter. I was happy with the way it simulated resistance. Out of curiosity I got a set of rollers with a mag resistance unit . If I train indoors, I primarily ride rollers. I think it keeps the workout more interesting, plus rollers build balance and pedal stroke. The only thing I can't do on my rollers is hard out of saddle sprints. I just jump of the drums. I'm going to remedy this with building a DIY emotion setup.