you can daisy chain up to 62 boards, allowing you to control amost a thousand servos! 
The resolution isn't fantastic - athough the 12-bit spec sounds good (4096 steps) you have to remember that if you stick to the standard servo update rate of 50Hz, and the standard 1ms to 2ms pulse width range, you only get about 205 discreet steps over the servo's travel range. You can do a bit better than that by using a faster refresh rate, which most servos are fine with - in any case 200-odd steps over a servo's travel is plenty good enough for most applications, and cheaper servos won't benefit from higher resolution signals anyway.
You can also use them for dimming LEDs, so even though 16 servos seems a ridiculous amount, 6 servos and 10 LEDs seems quite reasonable. Ideally you'd use a higher PWM frequency to dim LEDs, but you have to use the same frequency for all 16 channels, and for ordinary servos you want to stick to around 60Hz - and 60Hz works okay for LEDs too.
