I to have a CPR aquafuge pro,and it has been a great addition. My tank is pretty small so this why I made the choise of a hob.A hob is conveniant and get the job done.A full under the tank refugium will give you better water volume and less nutrients do more bigger water volume,and you can drop your heaters,and skimmer there also.A under the tank will need a overflow to be setup if you tank is not drilled.Overflows generate alot more noise since the water constantly draining,also if the power drops out you can have big mess on the floor.Hopefully some others will add more opinions here