Assuming both can remain healthy, Brand is by far the better player out of the two and much more versatile that JO is. The speed Brand has for the size that he is awesome. JO might have more of a post game and Brand does, but overall I think Brand is the stronger of the two.
I personally think overall the Sixers are the stronger squad too. Outside of our "Big 3" and maybe Bargnani
the talent level falls off quite considerably. The Sixers definitely have a lot more depth to their team this year something that we lack grossly and at this point is a concern.
As mention already though, both have struggled with injuries throughout their careers. So it'll interesting to see what transpires.