I'm, not familiar with the MF stuff. Thought my buddie in Chicago felt it sounds almost as good as the McCormack dna1. Anyway, I've enjoyed the Sonatinas for over two years and have paired them up with three tube amps: GTA se-40>VAC pa 35/35>Moth s45. Each are quite different in power, topology, output tubes. The VAC is 32wpc pp triode, the Moth is 2-6wpc SET. The GTA is not in this company. The VAC (tricked-out) was a fine mate to the Sonatina and I enjoyed their company for two years. But something was amiss, and I turned to SETs, hoping to discover the magic so many speak of regarding those designs. I'm glad I did. The Moth is a custom-built amp with upgrade parts I selected (Kiwame resistors, Exotic coupling caps, CTC "Blowtorch" silver wire). I've been enjoying it for a little over a month and I'm finding each week I like what it does more than the last. The Moth s45 is switchable between 2a3 (3-6wpc) and 45 (2wpc) output tubes.
The bass performance is better with the Moth, I especially enjoy the propulsive manner of the 45s. While I suspected some leanness issues with the new pairing (BTW - no preamp, DAC direct to amp volume control) as the amp has stabilized I'm feeling less and less suspect. The fullness that the stout VAC provided is reminescent in the new system as well. I don't know what to tell you, the leaness problems I found with the Sonatinas were corrected with a number of upgrades, and fine-tuning: Power cords/PLC, nos tubes, TubeTraps, interconnects. But rather than bandaid a problem I would suggest you look into your core components. I would consider a tube amp (there are many fine samples). The room may be a bit too large, especially if he likes to rock-out, for a SET amp (my room is 14x20x9). If he doesn't want to buy an amp, how about a tubed pre-amp. That is something I'm looking into, and will certainly add some "meat to the bones". Tubed preamp, BMI Whale pc, Bob Crump interconnects should all help fill out the presentation.