I've seen the RK 2 in person and it's a pretty neat system. - I went with the Aquatronica myself but know a supplier in Canada who sells them and have spent considerable time in front of the unit, and grilling him on its operation.
Prairie Reef Supplies is a distributor of them. I have been considering getting their "Power Bar Savers" as recommended by many people from RC to integrate into my system. Anyways - sorry for the thread takeover and good luck with the sale.