While a great concept and one that is lauded by many individuals, including Andy Beal and folks who like Matt Cutts, any blog that is always being tweaked on a regular basis should not be using WP-Cache.
If you know your blog is in perfect shape and never will be modified, then sure, this is a nice tool for you.
But I don’t like it.
I’ve been working on optimizing one of the blogs I maintain. For some reason there was an error on one of the pages and I couldn’t for the life of me figure out what was up with it. I removed the entire code snippet and refreshed a bunch of times. I even tried a different browser and then two different computers and four more browsers. And the code snippet was still there.
I realized that the error of my ways was this “faster WordPress plugin.” The files are all stored on the server and not processed locally, and the cache hadn’t expired. Therefore, I wasn’t seeing the newest updates; I was seeing a cached update — and there was nothing that I could do within my browser to change that. Still, the plugin is practical, but it just doesn’t cut it for folks who like to try out other plugins, new CSS styles, or make small edits.
Had I realized that WP-Cache was causing me considerable time troubleshooting and debugging code, I’d have stopped it immediately. But now I know what the cause of the error was — and I’ve disabled it.
The idea is still a good one, but you’re likely to forget that it’s installed and active when you’re busy fixing other parts of your blog.