Ok, had a short listen yesterday so keep this quick. Listened back to back in the following order initially;
Arcam FMJA18 - CD17 - Rega R3
Reasonable soundstage but slightly unfocused, sweet treble, slow not very defined bass, lack of drive.
Arcam FMJA18 - CD37 - Rega R3
More focus, performers move back, more air, good treble, reasonable bass, lack of drive
Arcam FMJA28 - CD37 - Rega R3
Nice soundstage, focus, informative clear treble, better bass but still somewhat loose and too warm at lower frequencies. Still lacks some drive and bite but good for fatigue free listening.
Naim Nait5i and matching i player - Rega R3
More drive than the Arcams with better 'leading edge' detail. A together sounding combination but soundstage is 'clumped' together between the speakers, treble is slightly harsh and stands out as a separate unit and bass is a tad woolly/not delineated, probably the result of a low damping factor, common to naims.
cyrus8vs2 - CD8se - Rega R3
More muscular sounding than previous combinations, clear integrated treble, good leading edge detail and drive, better soundstage than Naims, a tad less than the Arcam 28/37, better rythm/musicality than both the others. Bass very slightly loose but more powerful.
We changed speakers for each combination between Mission 790/794, Dynaudio 52SE, Monitor Audio RS6 and Rega R3. As I did'nt have unlimited time we've only spent a couple of hours so this is just a short, initial impression I had and the Mission were brand new and not run it yet.
Of the speakers there is only one clear outstanding performer and I'm sure you guess which one. The Dyns, as good as they are really need more powerful amplification than what we've used to bring the bass under control. Nice mids/treble though. The baby missions have a lovely midrange/reasonable highs but lack any form of bass, the larger 794's sounded good and will probably get better and both look sublime. The MA's sounded brash and unfocused compared to all the others. The Rega's took all the best bits of the ones we had at hand, made the best match with the gear we tried with an even balanced, focused sound with great clear bass (if that was available from the components) and good treble, they just sounded right though not quite as open as the dynaudios.
Obviously this is only my opinion, hope this helps someone.