I don't have books for both, so I'm not sure. However, in reading reviews at Amazon it seems to me there are differences.
Paula Nadelstern's kaleidoscope quilts seem to involve drafting and are more elaborate.
The OBW quilts seem to be similar to Stack 'n' Whack in that you stack the fabric repeats and then cut all the pieces together; however, the reviews indicate it is different than SnW and there is mention of forming hexagons with the pieces. All I remember is that, after I got my SnW book several years ago and looked through it, I thought I'd try something else! I guess OBW didn't tempt me after that.
Of course, there is the traditional kaleidoscope pattern which is simply a regular quilt pattern and does not involve cutting repeats of a fabric.