I went from a few years of barely using a KK fluid trainer because I disliked it so much to really increasing training time after purchasing E-Motion rollers. I cannot say that my bike handling skills improved more, but as an indoor trainer it certainly was a whole lot more pleasurable to use daily and for longer periods of time. The reason I went with the E-Motion rollers was the ability to set the resistance. At level 1 I can train up to my FTP using gearing as well to adjust on the fly resistance.

But then I bought a Kickr Gen1. With the two sitting side by side I tend to jump on the Kickr almost all the time. For indoor training I typically have a training structure that I would like to keep and the Kickr / PerfPro /power meter combination seems to fit it better for what I like. If I had a smart trainer first I don't think I would have bought the rollers.