I am using NSNetServiceBrowser from Xamarin (former Mono Touch) to scan for bonjour devices. This works most of the time, but there seems to be
a) a big caching issue, where it doesn't realize there are new devices b) a problem with the WIFI, e.g. when I turn off the wifi and turn it back on then
Most of the time, the Apple Bonjour devices are found, but avahi based devices (network printers) are rarely shown in the case of a) or b).
I am aware of NSNetServiceBrowser/Bonjour issues on iOS by the way.