It would be braced all around the rim of the tank and as it's square would probably have two braces crossing over each other from each side at least. This can all be hidden with a black strip around the top edge, so you don't actually see them when looking at it head on.
It all depends on exactly what you're wanting to achieve as to if it's worth the extra dollars. If you just want a clean looking setup with maybe a light suspended above, braceless is the way to go. If you plan on having a hood for example, there's no point going braceless, all the cost would be hidden. Is this for a project in the back room, or a major feature of your home? All needs to be considered.