I use standard biopellets on a home-made reactor similar to nextreef SMR1 for few years now.
And I'm just about to build a recirculating one for a friend of mine. The design is based on
http://www.reefdynamics.com/Reef-Dynamics-Bio-Pellet-Reactor-Model-BPR135E-p/bpr135e.htm
IMO, a reactor such as nextreef would do. Even my DYI reactor is set&forget. I just clean it once a year and add more pellets to it. I would expect that nextreef is as reliable if not better.
I don't really see the need of a recirculating reactor, but it's up to the owner. My buddy likes to test his water, adjust, re-test,repeat

. A recirculating reactor would fit in his setup!