I'v never tried a Marshall MG. Only solid state Marshalls I have experience with are the old 80s lead combo amp that sounds shockingly good as an 80s rock sound and some valvestates that belonged to other people. The valvestates are kinda amusing but not particularly great. I think its the preamps that sound shitty. Marshall coulda just given them typical Marshall tube amp pres, but they didn't want to use more than 1 tube in the circuit so the pre is areally hybrid and the tube isn't run at full voltage as I recall so its kinda like putting a tube overdrive in front of a solid state amp or into the PA. Weird sounding. I am sure the MG amps suck a dick. Everyone ahtes on them.
Now get ready for my to drop a major snob-bomb on you and share my real thoughts:
To be honest, I won't plug my own guitar into anything that's not handmade and tube based anymore unless you pay me to. I was even looking askance at the AC30HW I bought until I plugged into it because I wasn't sure I trusted Korg to make a proper sounding AC30 since every so called "handwired' amp they have released to date has been partially PCB, loaded with shoddy components AND HAS NOT SOUNDED VERY CLOSE TO AN OLD VOX (even when they had the sense not to load these amps down with pointless modern features, though many of them were totally bastardized on top of the questionable build quality). I was feeling snobby til I turned the old girl up and heard her great note definition, vox sparkle and felt the touch responsiveness as overdrive sets in.
I am sure there have been huge leaps in solid state technology, but I probably will not give any of these amps more than a few minutes of my attention in a store after trying the orange microterror and the ac30vr. Serviceable stage amps voiced to copy some old sounds, but not much in the way of real tone that makes you play better when you hear and feel it. Even mass produced tube amps leave me so flat I have trouble motivating myself to play through them. I plug into an ac30c2 or a generic channel switching amrshall at a store with nothing else and it feels like my tone got sucked down to a 2d, flat impression of my playing. The good stuff just sounds that much better. I try not to be snobby on this site because everyone has different depth pocketbooks, but that's how I really feel. If you aren't going for the top end products with simple circuits that let your signal breathe then all you can expect are serviceable sounds. Anything is good enough for live work though. Summoning amazing tones every night has never made me a dime, but songwriting has. You do the math. I still can't stand a lot of the stuff I get stuck using to try guitars in stores that don't stock high end and boutique amplifiers. Apparently its mostly just me who finds a lot of this stuff to be ear piercing and less musical than what I have at home.
I am still itching to try helix though sicne you can disable the amp modelling if it elaves you unsatisfied and just use it as an effects unit.... I am really into the TC stuff I've been buying though. I really don't want my dry signal turned into ones and zeroes. Its bad enough recording into a computer. Meh.
But yeah, sometimes I have to plug into a marshall DSL or something like that and I get a passable sound in a few knob turns, but its hard to hold my gorge down. Only the knowledge that if I vomit right on the amp the store might make me buy it helps me keep my lunch inside my stomach when I hear what passes for clean tone in most amps made since the 80s.