I disagree with ehider's conclusions.
I've heard both the Merlin with BAM and the VMPS RM-40 on several occasions and at some length each. The Merlins were always driven by Joule Electra tubes, worth more than twice the cost of the speakers of about $8K, and the VMPS by Ampzilla2000 solid state amps worth $5K, about the same as the VMPS speakers at $4.6K.
ehider suggests that "As long as you are not looking for the absolute best sonic detail ever imagined from the VMPS, you will not be disappointed." We disagree on that point. In my view the VMPS ribbons surpasse any cone speaker I've ever heard, including Wilsons and JMLabs, and Dunlavy V or VI. No contest. For transparancy they are in the company Sound Labs, and MBL. I've not heard anything from Genesis.
The Merlin are a delight to listen to, go much deeper than one has any right to anticipate, and can fill a room with pleasing sound and have good dynamic response. They won't play at ear bleading levels, the way the VMPS would, but who cares. Unfortunately, they are not the value that VMPS is, even with the $1200 cap upgrade to the VMPS, which I have not heard.
If the VMPS have a flaw, it is in tweeter directionality. Treble falls off vertically. If you only sit to listen, you're fine. An advantage to that limiation is that the treble tends to not generate ceiling or floor room reflections which subtally polute the transparancy of many speakers. I know of no speaker at any price that is a better value for the money, and wish I owned a pair.
Incidently, the localized treble "problem," if you want to think of it as that (I don't consider it such) is cured with the VMPS RM/X which has a different ribbon tweeter that is down firing from the dop of the speaker at an adjustable angle. It has two more midrange ribbons for a total of 6 per side, and crosses to the tweeter lower which makes for even greater clarity. Andy they play deeper than any speaker or subwoofer I've ever heard -- clean solid beautiful base, without any boom, and all perfectly integrated. The same tweeter is apparently available for the RM-40 with a different crossover, for even improved transparancy and efficency. I've not heard that upgrade.
The Proac 3.8 I heard once in a shop with both tubes and solid state power. They look beautiful, but in my view are not sonically in the same league with either Merlin or VMPS.