I have the RX-V1, have used it with several speaker sets, all in 5.1 config. I am not familiar with the Marantz or the Marantz house sound. I have found the RX-V1 to be pretty versatile, warm, and pretty musical in two channel. I have moved on to other gear that keep it for a second system, but still love it. I have tried it against some other THX rated gear, I don't place much credit in that rating.
Which speakers are you using? Are you using external amps or the RXV1's own amps?
Which speakers are you using? Are you using external amps or the RXV1's own amps?