You're going to pay more for the I/Os (unless you really shop around, there might be cheaper sets on ebay).
I have a pair of I/Os and I love them. Easy to change out the lenses, Smith has TONS of lens and frame options so you can mix and match, if that's your thing. Plus, the I/Os just look SWEET. Functional and good looking. If you buy retail, you get a lens for all-around conditions/sunny days and a lens for flat-light.
I don't know anything about the Kaleidescopes but they seem like a solid middle-of-the-road goggle.
Smith I/Os are really popular, and for good reason. I could be wrong but I think they were one of the first really successful models to incorporate a lens swapping system. You'll see a lotta skiers and riders wearing these.