I run a popular online adventure travel magazine and as traffic kept increasing and the site had more and more photography content on it and lots of plugins running to make everything work, page load times got slower and slower and hosting resources were being pushed to their limits. I've tested out all the other caching plugins and have found W3 total cache to be the hands-down winner. Combined with Cloudflare (which is easy to connect to W3tc) the site loads very quickly and has no problem handling heavy traffic now.
It's worth fiddling with the options to find exactly the right combination that works for your individual site. While some other caching plugins don't require any time to set-up, the results just don't compare!