If you get the rollers, be careful not to let your mind wander. Three days on my "new" rollers and I was doing intervals this morning. At 115 RPM in my hardest gear, heartrate at 183 bpm for a minute, I was doing fine. However during the one minute cool down I let my mind wander for a few seconds, thinking about summertime, and next thing I know I am on my a**, bike sprawled across the floor, brifter bent over. They are fun as heck, but they are work. Honestly they are not as much work as a fixed trainer, from a fitness perspective. But they are more work mentally. Honestly if I could I would have two trainers - a fixed magnetic/fluid type for strength/intervals at typical cadences (80 - 90 rpm) and rollers for the off-days to work on spinning/aerobics/high-cadence work. My rollers have 4" drums and roll very smoothly. I think I would also consider getting the 3" drums for increased rolling resistance.