free version
WP Rocket WP Fastest Cache WP Super Cache W3TC
Database optimization N #1 plugin for Database optimisation. premium premium M M
Image compression N 100% free, no limits* MRequires a separate plugin premium M M
Page cache N At least as good as every other caching plugin - see benchmarking results premium N N N
CSS and JS minification N premium N M N
Mobile specific cache N premium premium N N
GZIP compression N premium N N N
Preload cache N premium N N N
Simple setup N premium N M M

* most other image compression plugins have a monthly limit