i have the 12 and really like it. Just have a plan on what you want to keep and reaserch modifications that you might want to make depending on what you plan to do. One i really suggest doing is blocking the lower intakes and maybe even part of the upper one so it surface skims better. Another i have done was to make a fuge in the back. All the mods are easier to do before anything is in the tank.
edit: another one if you want to go reef is to upgrade pump to a mj1200