The reliability of UDP is mainly going to depend on the end nodes you're trying to connect. The backbone of the internet is very reliable and if you're connecting over ethernet or through some other wired connection you'll see very few dropped packets and thus UDP will be very reliable.

If you're connecting with wireless, expect to see some more dropped packets, and if you're connecting with bluetooth expect to see even more (because of its low power bluetooth is more likely to drop packets than either a wifi or wired connection).