We are with the no rocks cohort. They don't give you all that much
surface as compared to plant roots. Easy clean bottom is overwhelmingly
best.

As an aside, my pond build will featuring a sort of false bottom;
think egg crates (small pallets really) raised off the bottom, with
small flat stones on top of them to hide the egg crates. This is
because I want to create a hiding place for certain species that
are shy. The design features the bottom drain pulling from under
the rocks; my theory here is that small bits of detritus will be
pulled to the settling tank.

I really have no idea how it will work out. Just this whacky idea
I have. Note how if it doesn't work out, the whole thing can just
be removed. I then I have a flat bottomed pond.

C//