I believe GCE has a price/performance advantage in basically all categories against both AWS and Azure (one wrinkle is we don't offer small slices of
local SSD, instead pushing people to either our 375 GiB per unit local SSD or our Persistent Disk SSD product). For example:
https://cloudplatform.googleblog.com/2016/01/Happy-New-Year-...
As jsolson mentions elsewhere, we run PerfKit and compare ourselves all the time (both on raw performance and price/performance).
Disclosure: I work on Compute Engine.