I have tested using Chrome, Dolphin and the stock browser on a Samsung Note 3. In my office someone tried with a LG Android device running the stock browser, and another person with their iPhone 5. We keep seeing the full site instead of mobile.
On my desktop, I have the User-Agent Switcher plugin for Google Chrome. The mobile site loads when I switch the browser on my desktop to Android and iPhone.
I am not running a caching plugin. My site is using a modified version of the free Responsive theme.