Let me swim against the current. Every Marantz I've heard seemed overrated to me (I own five Marantz receivers, none really big), and every Technics receiver I've heard sounded at least as good (I own four currently and have had two others), if not better. I'm not saying that Marantz sucks, far from it, but the passion of their followers never seemed completely justified to me.
And 15 watts vs. 120? Come on! Unless you only listen to music with no dynamic contrast, then watts count! Sure 15 watts can drive efficient speakers to decent levels, but where's the reserve when it's needed? And what if you find a cool pair of speakers you like that aren't efficient?
disclaimer: all of the above refers to real watts, not magic watts such as the ones you might find in a cheap modern home theater receiver.