While I have never owned or heard any of the Grand Integra amps, specifically the M510, they were considered competion for the Mark Levinsons and Krells of the time.
Here is an interesting snippit. I can't remember what site I got this from.
"In a recent review, Stereophile indicated those Onkyo amps were competitive with the Krell and Mark Levinson models of that era. Those gold-toned Grand Integras were also popular at high end audio shows, particularly in the early home theater demos (this was before the advent of multichannel receivers, and right when the first consumer Dolby Surround decoders became available). I recall one setup using a Novabeam front projection TV, and the audio driven by a pair of monobridged Onkyo Grand Integras, with surrounds driven by another two-channel Onkyo amp."
Bill
Here is an interesting snippit. I can't remember what site I got this from.
"In a recent review, Stereophile indicated those Onkyo amps were competitive with the Krell and Mark Levinson models of that era. Those gold-toned Grand Integras were also popular at high end audio shows, particularly in the early home theater demos (this was before the advent of multichannel receivers, and right when the first consumer Dolby Surround decoders became available). I recall one setup using a Novabeam front projection TV, and the audio driven by a pair of monobridged Onkyo Grand Integras, with surrounds driven by another two-channel Onkyo amp."
Bill