After listening to M3i for 2 weeks, I believe it has fully run in based on over 300 hrs of continuous driving the ProAc and I cant hear anymore big difference in the music. My ears are now acustomed to the M3i sound that I think I would not be able to hear any different runing the M6i. Boy, was I wrong !!!! The M6i came in a similar package as M3i except for the black velvet bag. Dont know why is that. Although this is an open box unit as the dealer gave me the demo set. Taking it out of the box needs a bit of effort as it is a heavy unit, built like a tanker. The sides part is of grilled design for better heat dissapation I suppose. The fascia is similar to M3i but the height is bigger than M3i. I set it up similar to how I set up M3i but I just placed it on the top shelf. Some ppl say that amplifier sounds better when placed at bottom shelf but I could not squeeze that extra energy at 2 am to do that. Went in French Kiss OST with Kevin Kline on La Mer. Hhhhhhmmmm this is what surprised me. I can instantly hear the difference. The song sound more 'airy', vocal was livelier and the musical instruments seems to be more upfront. NOTE: this is a run in unit. The CD was played via the M1 DAC, For my normal listening level (10 o'clock on the knob), it seems louder than M3i. I reduced it to be at 9 o'clock. All this however was before I went to bed at 3 am. That would be my first impression of the amp but not truely an 'out of the box' review as the unit has been run in. Will report more over the weekend.