I am in the process of planning for a 300 gallon. Bare bottom was never an option(ugly and unfinished look). I am however considering slate plates for the bottom in the areas that I have rocks and sand in open areas.
if you want no maintenance, bare bottom with a small powerhead sweeper. Not a huge fan of bare bottom.
Bare bottom all the way...............Less mess, more water volume..........
Everytime I've gone BB (small tanks) waste is always floating around and the tank always gets cloudy. I also don't like the look.
If yours is staying clear with the BB then that part of my comment is invalid.
thats what I want exactly and what I'm doing, but always want to try 3m but don't want an require work in maintaining 3m.
In my opinion a bare bottom tank looked a bit more "Professional" from my standpoint because it is a lot easier to maintain, it saves you some time without having substrate in your way while cleaning the tank, fish feces gets picked up by your filter a lot easier, Its easier to observe your fish, the risk of parasites is reduced, and the tank looks a lot cleaner in my opinion.