Which tree to track: linux-next or staging?

Hi

I have had the opportunity to submit a few patches, which has been
really fun. However, a while back i submitted patches for fixes that i
realised after had already been patched in GregKH tree ... and i
realised i had been developing against Linus's master branch, and not
linux-next.

But my question is, is it better to develop against linux-next or in
newbies cases, one of GregKH's (staging) branches? Maybe
staging/master or staging/staging-next?

If you develop against linux-next, dont you run a pretty big chance of
someone submitting to one of Greg's staging drivers prior to the merge
into linux-next, since patches go to drivers/staging seemingly a lot
more frequently than the merges into linux-next?

Thanks in advance
Cheers
Jon