I really like having a set of resistance rollers so I can use a big gear if I want serious resistance. My old set doesn't have a lot of resistance, but I can get into Z4 at about 70 cadence in my 53 X 12. I can do any workout I want on them which is nice for rainy summer days. I don't sprint on them - no point in sprinting on indoor equipment since it doesn't translate to outdoor performance because of the lack of mass to accelerate.