i think there are more than a couple of things at play with the fox/reba debate:
1. the offset of the fox
2. the poploc action of the reba
3. the weight of the rider
4. brand loyalty
generally speaking, the "research" that i've done leads me to believe that based on my weight the fox would be a better fork. the fox is supposedly a tick or two stiffer than the reba, which, again based on my research, folks in the lower clyde regions and upper "normal" weight regions, deem a bit "noodly".
i did ride a reba sl and didn't notice anything but that was over a year ago and my first go on a 29er. oh, and i haven't ridden a suspended bike but three times in the last year so you can pretty much toss that observation right out.
but that said, i never had an even a little issue with the reba SL on my trek. that thing always worked perfectly.
i don't know which i'd buy though. i think i'd do all i could to ride each one back to back on the same trails to see which felt better. i guess that's my answer.
brett hates them both, btw.