Last time I checked the Oppos only went up in price after being discontinued, even the used ones and there is not many of them for sale where I live.
How is the sound quality from the analog outs on the Oppo?
Used Oppos are commonly for sale on the used market in North America. I didn't know they are rarer in Europe. I followed used 103 pricing for a while when I was looking for an SACD ripper (eventually settled on a new Pioneer). They did seem to hold their value well, but they could be had for significantly less than new cost. I have an old 83-SE that I seldom use anymore (all my music playback is via rips now). The cost for that model on the used market or even the next 93/95 series Oppo is considerably less. It would do all your Marantz can do now plus added HDMI capabilities and blue ray (does your Marantz play BR now?). Lots of new releases on BR now.
The sound quality of the analog section is one of the big plusses with all the Oppos, that along with the utility of offering DAC processing from external sources. Upgraded DACs are in the xx5 models. So if that's important to you look for 95, 105s or 205s, which are significantly more expensive. Its not clear to me though if the upgrade in DAC quality is as large with the MC performance as it is with Stereo performance. There may be differences in the stereo vs MC DAC specs in Oppo units, There certainly is with the stereo DACs in my 83SE being more high performance.