I had an Oceanic 30g cube with a sump and all of that jazz. I also have a 14g BioCube. I had to replace the Oceanic system with a tank with a smaller footprint (due to the sump, my stand was larger than the cube) and that led me to the Solana. I would describe it as something between a BioCube-type all-in-one and a full system like my Oceanic cube was.
As far as the things it's lacking, well, there a few. It needs a good ATO (just like any tank), it needs a few additional powerheads or a single mp10, and lastly, it probably needs more light. I have the disco ball and I just don't think it's quite enough. I'm probably going to bump mine to the 250w radium that was over my Oceanic cube. It's not a necessity, but I'm doing it. In full disclosure, the bulb in my Disco ball is WAY overdue for replacement.
My only real complaint is the price one pays for a rimless tank. It's very easy to splash water out of the tank when working in it. I have to have a towel in hand when I clean the glass, every time. The rimless look is worth it though. It allows the tank to fade away and let the coral take the show.