Having had a recent Marantz SR6001 amplifier, and now having the Denon 1911, I'd say that the Marantz gives a slightly richer sound, but the Denon has deeper and better controlled bass, and a little more detail.
Overall, for my tastes, the Denon edges it, particularyl for films, but the later Marantz amps have made big performance strides.
However, they both have quite a similar sound. For example, the Denons were the only amps when I demod that gave a similar musical presentation.