Warm, deep and effortless sound. Great combination with KEF LS50s

VERY, VERY nice sounding amplifier. If you want to see what this amp can do you must surround it with great components and use quality cables. I use an NAD 546BEE cd player as my main source running through an ARCAM irDAC and feeding Monitor Audio BX5 speakers. Cables are Audioquest Cinnamon with Audioquest Rocket 44 speaker cables. Wow, what an improvement over my Yamaha integrated amp. This amp creates a full, smooth, punchy, yet very detailed sound. The soundstage is large and very stable with excellent instrument separation. I can't put my finger on it but this amp with my current setup just adds a but of magic to my music through it's unique british sound signature. Very highly recommended.

Writing a quick note since I don't see many reviews for this amplifier online, perhaps because it is relatively new, though its predecessor M3i seems to be quite well regarded. I just received it yesterday and have set it up with (the superlative) KEF LS50 mini-monitor speakers and an REL T-5 subwoofer, the DAC I'm using is the Oppo HA-1. The amplifier arrived well packed double boxed and the amplifier was enclosed in sturdy molded Styrofoam. Musical Fidelity covered the amplifier in a black velvet string bag which is a nice touch, they also include a pair of white gloves (and a microfiber wiping cloth) to handle it. The construction is pretty solid and it is a large enclosure (~400mm) with the width and the depth almost the same, take this into consideration if you already have a pre-determined location for the amplifier. The manufacturer specifies it at a healthy 90W per channel with total harmonic distortion rated at < 0.014% under typical use. The circuit according to MF is a class G (my understanding is that this means it is class AB with dynamic power down) and runs only slightly warm. The M3si usefully also includes an asynchronous USB-B port capable of 24-bit/96kHz input which I haven't used since I have a dedicated DAC. I'm using this for my desktop setup with aforementioned equipment and is probably overkill for it, but it provides sufficient headroom and drives the LS50 at comfortable listening volumes at about the 9 O'clock mark (zero position around 7 O'clock mark). I'm no audio expert but the system sounds amazing streaming CD quality music from Tidal. For example, the track "Like A Dog Chasing Cars" from The Dark Knight soundtrack has never sounded better to me, vocals also sound fantastic e.g., Adele's "Someone Like You." The amplification sounds very neutral to me and there is no noticeable distortion (to me at least) even at high volume, also there's zero hiss at full volume without music. The volume control and other buttons have a nice weighted feel to them that scream high quality. The speaker binding posts also share this property. The only let down is the plasticky remote control which I thankfully don't have to use since I've set it at arms length. Overall, I can't be happier with my purchase (though I've used it only for a short time) and I'll try to update the review after some time in case my evaluation changes with use.