The only thing I didn't like about the Mazda was that it felt cheap. Thing sounded like a tin can when I shut the door.
I may be one of the few who have gone from an NSX into a FD and I couldn't agree with you more. The feeling of driving a tin can is only amplified when you get going down the road! The NSX isn't exactly a lightweight but the use of aluminum obviously allowed Honda to build a very solid car at a substantial weight savings. Mazda took a more conventional approach to weight savings which resulted in much lower cost but also gives the car a 'cheaper' feel.
Like you said the FD definitely has its charms as does the NSX. I think both cars' styling has aged very well and I probably get as many people stopping me in my FD to ask what it is or admire it as I did in the NSX. My FD is much faster than the NSX but as others have mentioned its not really a fair comparison when you're talking about a highly modded car. Both are great cars just very different in how they achieve their goals.
Nate