Technically, Music Direct is the parent company of the current incarnation of Mobile Fidelity Sound Lab, as well as their more recent venture, MoFi Electronics. MoFi's current speaker lineup was designed by industry legend Andrew Jones (formerly at KEF, Infinity, Pioneer, and ELAC) and all three models are widely regarded as some of the best in their class for the price. As for their other gear, I don't know.
The issue with MFSL SACD releases of albums with quad mixes is that they acquire exclusive licenses to the titles they put out, such that another third party label in the U.S. interested in releasing the quad mix (e.g. Audio Fidelity, R.I.P.) cannot obtain a license to do so at the same time. Because Rhino is under the Warner umbrella, they are a first party to anything owned by a Warner label, and therefore are not bound by such third party exclusive licensing. You'll note that the recent Yes reissues with LPs and Atmos Blu-rays, on Atlantic/Rhino, coexist with third party licenses of those same albums to Analogue Productions for their Atlantic 75 series of SACDs and LPs.
It is indeed good that more retailers are stocking Quadio, though it would be even better if there were no period of exclusivity to the Rhino store, and all titles were available at launch from multiple sources.