I think the d300s is suitable for people who have bigger hands that need a bigger grip. I prefer the ergonomics of a smaller camera, since i dont have huge hands. The d300s would suit people who love shooting sports, or need lots of convenient controls located outside menus.
not really i think..i've small hands and when i tried the D7000 with the 70-200 2.8 at the clubsnap kopi session, it's quite difficult to grip (too small and feel like plastic). the d300s is a few times better in terms of grip, ergonormics.
if new technology is not a concern and u intend to use the heavier FX lens on a DX camera, i still think D300s is a better choice.