Traditionally nokia's mid to low-end phones (s40) have had very good build quality and materials, usually better than N-Series devices. I think at some point better specs hardly improve the user experience on a N9 form factor. After all its designed for one-handed use and has a relatively small screen. On such a device most people won't do any productive work which requires lots of computing power. That said, the n9 could need a bit more power here and there for some tasks. It can be seen with the iphone4s, which most people probably won't buy just because it has a dual core.