I just purchased a set of Sportcrafter ZRO rollers. They should be delivered next week. In the research I've done to decide on what to buy, I was interested in the E Motion because of the "floating" feature that reportedly offers an easier, more realistic ride. And helps prevent the bike from jumping off the rollers when standing and really spinning up. I wasn't prepared to spend the $800 for this setup so dismissed them because of that. But it wouldn't be too difficult to modify the Sportcrafter unit with some skateboard casters to accomplish the same results. My question is: How real is this perceived advantage. Or is it really just marketing hype? Might it mask poor pedaling technique and therefore actually be detrimental to developing a smooth 360 degree pedal stroke. As for the "training wheels" that keep you from riding off the side of the rollers, I'm sure these provide some comfort to someone new to rollers but once you become used to rollers in general you should be riding down the center anyway. I tried out a set of Kreitler rollers borrowed from a friend for a couple of weeks and admittedly the first few times I tried them (in a hall way as suggested) I rode off them two or three times but since then it's not been an issue. So... let me know what you think about the merits of allowing the roller and frame assembly to "float" fore and aft an inch or two.
I love riding e-motions, but there's nothing wrong with regular rollers. The float won't mask bad pedal form on them though. The bumpers around the rear tire are better than the rollers on the front wheel, when you jump out the of saddle, the rollers will keep you from rolling off the front of the rollers. I would compare say e-motions are a jump up from regular rollers like rollers are a step up in fun from a trainer.