My good friend and i borrowed one of each of the above for an evening's listen with a mind for a possible purchase by my friend to back up his Rel Stadium given his listening room is reasonably large, both subs were connected via high level feeds from an Auberry integrated amp with an Arcam transprt and DAC as a front end. Our conclusions (which fly in the face of perceived wisdom here) was that the REL was CLEARLY superior, whilst not possessing the absolute grunt of the MJA it clearly was the more refinded unit able differenciate between graduatiions and decays whilst the MJA just wouldn't integrate, no matter how we set it up once it "engaged" it simply stood out as a seperate entity within "the mix". I was honestly surprised, given how many have said they prefered the MJA and although it goes somewhat against my love of HUGE sub's i actually felt it somewhat surpassed my admittedly low expectations. No doubt gent's under our "test conditions" the Rel was by far the "better" sub. Steve.