When it comes to CPUs and GPUs, faster is always better. But as with any mature market, at some point performance specs become a commodity and less relevant as a way to differentiate brands. Speed gets "good enough" and other factors have greater influence on brand perception and upgrade decisions.
I think we are seeing this pretty clearly already with desktop CPUs. Do you actually notice a CPU speed increase from 2.7 to 3.1 GHz? I don't. The same thing is starting to happen with discrete GPUs.
For companies like AMD, Intel and Nvidia this means finding differentiators beyond isolated speed benchmarks. This is motivation behind the "Beyond Benchmarks" posts on FireUser.