I have personal experience with REL, SVS, Rythmik and to a much lesser extent Martin-Logan. In my experience Rythmik has the best sound quality, though not by much, but if you have a penchant for loud bass heavy music, they may not have the power you would need for them to keep up. SVS in my opinion is a great value and should be able to handle anything that you throw at it. REL sounds okay but is just not worth their price. Unless you need the auto correction, I would look at the "E" series instead of the Fathom. Magico, I have absolutely no experience but they seem like an awful lot of money for probably very little if any audible improvement. I would definitley want to do an AB comparison before I bought them.
Of all the subs that you have listed, I would pick the SVS.