I have had both types of tank set ups. I have switched back and forth many times over the years, and will probably continue to do so. I think as long as you have places for the fish to hide, plants, things for them to swim through, etc., it doesn't really matter. I don't think they care if their gravel is purple and there are neon green rock caves, as long as the setting is natural (aside from colour of course!). I can see the appeal of both, and I think do whatever makes you happy, as long as it is safe and healthy for the fish.