I've used it in Mexico and most cities are 3G speeds (they use Movistar's network, unfortunately, so that means not a whole lot of coverage in less popular areas in Mexico). In Mainland China speeds were 2G, but still usable... but you get censored by the Great Firewall. Hong Kong I was able to get stable 3G speeds.
Like you say, being free you really can't complain haha. But I can tell you, having that as an option really makes a difference. It can save you from getting lost, translating things on the go... pretty nifty. All without emptying your bank account.