Here are they pictured side by side. The M300 is bigger and looks a bit like Rotel/Emotiva gear. I think it's nice looking except for the big Q logo on top of the amp. Overall it looks a bit less classy and exclusive compared to the Marschino amps. The M300 is bigger because it houses the power supply. So you can't upgrade the power supply for more power as with the Maraschinos. Okay, the M300 are a fair bit cheaper but it also looks more standard but not only that...
The Comparison was done by me and the owner of the M300's
Soundwise when first firing up the m300 (not new out of the box, they have more then a few hours playtime) they do sound good and in control just as with the Maraschinos.
They are certainly very good amps but before we switched to the Maraschinos i had a sense that the sound was a bit more darker and dare i say it less detailed. Everything else i heard was fine though. Switching over to the Maraschinos i instantly heard a more clearer sound without sitting in the sweetspot. When i comfortably sat down in the sweetspot i heard Mark Knopflers voice from the Dire Straits albums a lot more clear and lifelike. And man we both agreed we could here more details in the recording. My modified Carnegie Acoustics speakers with the detailed but silk bandtweeter lend themself very good to that. The owner of the M300 still defended his amps darker tone to some of the jazz tracks he listens to often. It suits the amps good and the saxophone stood that bit more out compared to the instruments on the background that sounded a bit muffled when comparing the same track on the Maraschino amps. But other then that he agreed they are certainly better and would replace his M300's to the Maraschinos in a heartbeat if he wouldn't have to pay the extra for the Maraschinos. But then again the Maraschinos are certainly worth the extra dollar over the M300's. They do provide a clear window over the music and delivers a sound that is cohesive and draws you in. And with the 60V upgrade they should give the Maraschinos a bigger soundstage and more authority as Tommy described. And i think it's fair to believe it will turn out that way with more power on board.
One final word...Since i bought the Maraschinos i didn't had the sense i want to upgrade components in my setup (except maybe for a bigger power supply out of curiosity), i just enjoy the music more without listening to the sound to check it's okay, it is more then okay and that puts me in ease to forget anything and just to enjoy the music.