I think the fit of the chair is going to make a bigger difference in which one is "better" than the upholstery, or lack thereof. My most comfortable rocking chair is a vinyl and crome one from the '70's. I like it best because it fits me best. If you had two chairs that fit equally well, I'd probably choose the wooden one for the reasons you state, but if I had an upholstered one that was super comfy I'd probably just throw a washable blanket over it to catch stuff. Also, I personally find rocking chairs far easier to deal with than gliders, partly because I can move a rocking chair while sitting in it with a sleeping child, but when I try to do the same with a nursery glider it doesn't work so well (it could be lack of practice).