I have not heard the VSM-MMs, but did hear the VSM-MXs a couple months ago on top-of-the-line gear setup perfectly. I own the Signature System (using not as high-end gear but still well matched to the speakers)...
I wrote Bobby an email after the audition and my bottom line verdict was for smaller rooms I would probably go with the VSM-MXs, and on larger rooms (like yours) I would take the Tylers.
The Merlins were in a small to medium sized room where I heard them in a generous owner's house that is local to me. Bobby facilitated the intro and then the owner and I did the rest (thanks again, Bobby!).
In the smallish room, the VSM-MXs were right at home... Vocals sounded *incredible* on them. I remember listening to Fiona Apple's Tidal CD, and the track "Slow Like Honey" was absolutely captivating. I don't think I have heard it sound better quite honestly. The top end was detailed, but not fatiguing in the least. Soundstage was not the speaker's greatest strength, but it got the job done... Low bass extension was the only "achilles heel" to my ears and tastes. Very strong performers, and perhaps the best two-ways I have heard.
The Tylers have much deeper bass extension (bass resolution was about equal, but the Tylers go much lower and sound considerablly fuller down low), and I felt they are a hair faster as well. Soundstage was also in the Tylers favor. Top end was a draw, and vocals I give a slight edge to the Merlins (and that is a strength of the Tylers, so the fact that I prefered the VSM-MXs on vocals is all the more impressive). The Tylers are also a bit warmer sounding (which can be a good or bad thing depending on someone's tastes).
Personally, I think for a room your size the Merlins are not as good a fit as the Tylers... If you had a much smaller room I might be changing my recommendation. I pretty much like the two speakers equally, but they have very different sounds and applications. The Tylers are a better fit for yours, IMO... the Merlins could very well be for others.
BTW: I use 3 Taylo Reference Monitors in the back of my system for HT and they work fine with the Linbrook Signature System speakers...
---Dave