I've actually asked a couple folks about this, but would also like to hear an opinions on Darkfield vs Phase contrast. I've looked at both
Most of my work with a scope is looking at live cells in tissue culture (inverted scope) and immuno-fluorescent microscopy. Phase contrast is what I and most others in the field use. Dark field works, but I think you can see more detail/texture with phase contrast. I think phase contrast would be best for reef micro-critters. Just my preference!
Bob