I use a NOVA as well. In fact I use 2. A three slot 12x16 for colour (RA4 and a 2 slot 12x16 plus an open dish for the B&W developer. They, NOVA are the epitome of superb simple design that just work with no fuss.

The real beauty of them is the very small footprint they have when left idle or even working. My darkroom is shared by my motorcycle (actually it is my garage) so space is at a premium. As Antmar has said chemistry life is superb, the RA4 I am using at the moment was first mixed in June 2012 and just replenished after each session (100cc per 800 sq inches of paper - pro rata)