Matrix says the sond has improved, they call it smoother and sweeter. Not sure how they accomplished that but a likely candidate is a different stock opamp. That makes sense to me. I think one LED is for power on, the other maybe has to do with USB signal lock? Just guessing here.
To answer the question about Lake People G103 - G103 is a bit warmer and smoother than the old M- Stage was in stock form. It has way more power and is a better match for planar magnetics of all brands. Matrix could be a bit more resolving up top, depending on the opamp choice. Both very good options though.
It's actually warmer? Hmm.. i have an HD600 and i was looking for a neutral amp in the <$300 range. I heard that the M-Stage was a bit warm, which gave me pause. After reading your review of the Lake People G103, which said it gets "out of the way of the music", i was considering it, but it seems it would also be a warm amp. And now Matrix says the sound of the M-Stage is sweeter.... T_T