Assuming you meant "Musician" instead of "Mission", I've heard both, but I heard them in two very different systems.
As always, the standard caveats (to my ears, IMO, etc.) apply to the following comments -
I heard the Belles at the Marriott in Denver, but the sound in Dave's room wasn't very good. The speakers were the new Usher monitors that had impressed me in the large Usher room downstairs, so something was definitely amiss. Unfortunately, I have no idea what in the chain (source, cables, amps, etc.) was the culprit.
I heard the new
Spectron Musician III Signature Edition at Steve Chang's via the SP Tech Revelations and was shocked by what I heard. Spectron has a reputation for being dry and analytical in some circles, but the Musician III SE is apparently a different beast, at least to my ears and several pairs attached to others.
I had advised Bob (Smith, of SP Tech) against expecting too much no fewer than 3 times before we arrived at Steve's place, but my preconceived notions about the Spectron were trashed in less than 10 seconds.
The Musician III/H-Cat preamplifier pairing - aided by a McCormack transport and (I
think) an Orpheus DAC - proved to be one of the most musical combos I've ever heard. The Revelations can be ruthless, but what we heard that night was shockingly good. If you've read the comments from that night, you already know what I'm talking about. Fast, smooth, accurate in so many ways... and yet so musical. It was truly the closest I've ever heard a system come to a live event, which quite honestly was *NOT* what I'd expected of the Spectron.
Again, I don't know what was going on in Dave's room, nor do I know what anyone thought about it aside from me and those accompanying me, but I have no doubt about which of the two I'd get.
In fact, I'm considering selling my Butler Monad monoblocks and replacing them with the Spectron. It was that good.
'Course, doing so may then lead to getting an H-Cat preamp, which in turn could lead to an Orpheus DAC, etc., but them's the risks you take when you dare to venture out and hear new things.

I'm sorry, but I don't remember... do you have a pair of SP Tech speakers?