I own both, love both. Both are stock with only suspension mods, both are dealer maintained except oil changes. Just for fun, I'll add up the receipts to determine which is the more maintenance heavy car. Both have 130k miles, and honestly, the rx7 is holding together a little better in my opinion. The stereo is not sounding too great on the nsx, the a/c is barely working, and the bolster is so worn its getting pretty ugly. My rx7 has some interior panels shaking loose.
The rx7 has had more "problems", but the NSX service visits feel expensive. My gut tells me the NSX was more expensive through the years, tb service, expensive clutch, etc etc. Rx7 was repeated vacuum hose issues, and cooling issues. Both cars have had 1 clutch, both have had some degree of warranty work, NSX more major, as this car was a snap-ring car. Rx7 was fuel lines. Anywhoo, when I get a chance I'll add up the receipts.
As for driving them, they are both awesome. I like the city feel of the rx7, torquey, lighter steering, smaller car... I like the high speed stability of the nsx and the better gas mileage is a huge plus.