I would say that Marantz gets mentioned in the same breath with Yamaha and the like because it is nothing to rave about. It fits in nicely with the mold...
But, I worked with Marantz in 2002 and customer service with them is almost non-existent if you have a problem. I also was putting it in areas where people wanted zone 2 functionality and it performed very poorly for this purpose. The Yamahas of that time did equally bad.
The next year Yamaha performed flawlessly for multiple zones, while Marantz still did not perform well. RS-232 for their product was also very weak, while Yamaha did very well.
Now, this has nothing to do with audio quality or sound, but it does say a lot about the engineers who are designing and working on their product. They may be focussed strictly on sound, but they seem to miss a lot when it comes to other aspects of their product.
I currently work with some other pieces by Marantz, only they are repackaged product from other manufacturers. So, Marantz is happy to take a competitors product, slap their name on the front, and resell it for more... then not really be able to support it. I won't be looking to purchase Marantz for a long time and I have always talked people into Yamaha when they had been thinking about Marantz.
THOUGH: I have not been unimpressed with the actual sound of Marantz receivers, or their performance, when set up in a single zone IR controlled environment.