In stock form I still pick the Modena over the 355. The driving dynamics, performance, and design of the 360 are evolutionary and progressive over the 355. It's a subtle change, but I think it carries a more modern interpretation of the exotic car look and style that brings it forward into the new millennium. 
Also, the NSX has never been competitive in the exotic car market for the last few years. Its simply too old, too slow, and too expensive for most of its competition (in which in todays market may compromise the Z06, 911, etc.). Being mid-engined and rear wheel drive has no direct correlation in performance nor targeted demographics. While there may be cross-shoppers of ferraris and NSXs, they are most assuredly quite few. 
That said, my personal preference is still in twin turbo vipers. Though i have seen a twin-turbo ferrari f50 thats fairly interesting.