[GadgetKen]

Still using my Koko Mobile sim card as a secondary sim in a rugged phone. In the USA, it will work on AT&T (my primary sim card is using a T-Mobile reseller called Mint)...no need to constantly top up the Koko card like a domestic prepaid AT&T MVNO.
It works fine when I am in Bermuda by USSD dialing. Other mobile alternative there were VOIP using a SkyRoam mifi device.
My primary need for Koko is really a backup sim that can use AT&T in the USA but also can roam in countries my primary sim doesn't work in (like Bermuda).
Also my interest in Koko is really for voice and SMS text messaging, since I can get data cheaper domestically or internationally through other means.
Like the switchable profiles and the USSD dialing capability.

My main reason for picking up a Koko sim card was the Piranha debacle...couldn't wait for Piranha to switch from Telna to Jersey Telecom as a background provider. The 2 Piranaha cards were eventually replaced, and now are used in emergency phones for my elderly parents.