Gnome's polish is probably the best of the Linux DE's but it removes far too much configurability and features (in the name of simplification) for my tastes. I'll stick with KDE. Each release gets more and more polished, and I'm very much looking forward to Plasma 6 and the Wayland Goodness it will bring.

Having said that, I think the competition between them makes both of them better so I'm glad that both exist. And where they depend on common libraries, both benefit once again from the contributions from the other's contributions.