Your report is false. The E-motions have some little skateboard wheels that you can bump against befor riding off, but you can certainly fall off. I've done it a couple times, both times watching TV where I was just zoning out and got too far to the side (up against the little wheel) and couldn't correct myself. That said, I've watched a lot of TV on these things and the little wheels work very well unless you are just in la-la land.

Like others have said, I think the key benefit is riding out of the saddle, banging against the sides, sprinting, etc. without going off the rollers (front, back, or sides). They are very forgiving, I was out of the saddle the first night I had them. I don't have any experience with regular rollers, but I'm guessing that the learning curve is much faster with the e-motions and there is a greater margin for error. If you are on a tight budget, I'd bet you can get all the same benefits from regular rollers, just with a little more practice (and concenration). The e-motions are pricey, but the workmanship/engineering on them is absolutely top notch and the floating design works very well.