I had the ML 383 for a short while cuz I thought it looked so cool. It was a very nice looking piece IMHO. It was fairly smooth and transparent but also analytical and a little lean in the mids. I think that combined with its 'polite' presentation in terms of dynamics is what made it a total snoozer.
I've had other 'dynamically challenged' amps but they were on the warmer sides so even though they didn't light my fire I would call them boring. I think the ML's sonic character as described above ALONG WITH its dynamically dead sound is what made it especially boring.
Not mine but here's an example ML 383
Very handsome and beefy I thought. But he turned out to be a mama's boy.
