Easy to install and setup, efficient caching system and free for basic use. It's easy to clear cache on any page with one click. Has so many option and easy caching exclusions. It makes saves server resource and it's also improves search engine ranking.

One of the best features that W3TC has is the ability to use Redis and/or Memcached for in memory caching of database queries, objects or even for the page cache. This makes allowing multiple scalabale instances to access the same cache instead of replicating it across multiple instances.

My website load speed increase by upto 30%, I also noticed improvement in pages with high media content, especially repeat visits. It augments some server lags, I noticed my website loads slower at some certain time, probably server is most tasked then, but with w3 total cache, this lag is hardly noticeable.