I've tried... I've really tried. Because when the plugin works it DOES increase the performance of my sight slightly. But it doesn't work with WPTouch... or just about anything else really. It adds about 500 lines to your htaccess to make use of some apache features, and the rest of the development on this piece of crap is advertisements. New Relic, Max CDN, everyone you can think of. This is basically an affiliate advertising link for a bunch of overly aggressive overpriced monitoring and CDN companies. The plugin itself sucks. It is terrible. I keep giving it the benefit of the doubt, but not after this time. And I'm not going to pay the developers $200/%15 minutes (all you see when you start this plugin is a dashboard of things you should buy, including their 15 minute blocks of support. The plugin just sucks. It's so bad, each time I've installed it, I've ended up with a web site down and having to go into the MySQL database to extract this virus-like plugin from my environment. It's a scam to get you tethered to them for services and for them to earn affiliate commissions from referrals. Not only that, but any performance increase when your website is actually up is modest. At the same time, the widget page of a theme that used to take 15 seconds to load, might now take 12+ minutes. Other than totally wreck your htaccess file, I don't know what this plugin does to screw things up so badly, but if you insist on trying it, I suggest you make a backup.
http://wordpress.org/plugins/w3-total-cache/
[mod note: NSFW topic title changed]