I've listen to the G55 (not broken in unfortunately) in 2 configuration: normal and brdige mode against Primare A30.5 (5-ch amp) and Stello S200 (2-ch amp) in a 2-ch setup (a bit unfair against the 5-ch amps).

Typical Meridian Amp, sound warm, top end slightly absent, bottom end there not very articulate and clear. The change between bridge mode and normal is quite astonishing: 2 words: more dynamics!
Compare to the Primare (broken in), beside the big price difference, the Meridian out class it, The Stello on the other hand was more linear with expanded extremes, slightly colder presentation of the music but more transparent than M and P.
what I would expect from my experience with M amps and the G55, I think the midrange forwardness will come down quite a bit with still some left over, the top end will not be flat and the bottom end improved just slightly (probably not a big enough power supply)

In favor of the G, a very flexible setup there are very few multichannel amps in the world that would allow bridging, cinch+XLR as well as double binding post for each channels for bi-wiring, small form factor, not much heat, good sound but not top audiophile quality.
I think I will go for it for my surround channels with the following configuration:
Center channel bridged 1x300w
2x surrounds @ 100w
and I will have a spare channel left over

my 2c
FB