Hello from Germany,
if the Bluefire SIM works well, some of us would like to have some details, e.g. like the Prefix for this card +44 7xxx x for example.
Most of us had bad experience with the gone "callkey" IoM card which disappeared from one to the next day. (Was sold under "Globalsim", "GT-SIM" and much much other brands)
Somebody here suggested the german-based vistream SIM-Cards.
vistream (powered by Materna) is a virtual network operator using the German e-plus Network.
Prefix is +49-1570-xxxxxxx
vistream Customers report about strange problems with Callback-Roaming in various foreign countries. It may work, but it may not work, too. German speaking/understanding readers could have a look at
www.telefon-treff.de for more details.
vistream uses a Dual IMSI SIM-Card with SAT-Callback, which is a little bit more sophisticated than the known SIM-cards from IoM, UM or other Companies. So should have a newer SAT-compatible phone (like Nokia 6310i or later)
As a addendum or backup to the Bluefire Card you should give United-Mobile a try:
UM offers two tariffs/cards:
UM423 (based in Liechtenstein) includes a lot of countries like China (PRC) where incoming calls are free. You can get one in a Swiss Postal-Office or mobilezone or from
www.callfrom.de in Germany (not listed on this page)
Disadvantage can be the prefix +423-663 which is billed premium-rate in some countries.
UM+ (based on Isle of Jersey) has less countries with free incoming, but offers some countries, the UM423 does not and vice versa.
UM+ SIM-Card is available from
www.united-mobile.com
There are some threads in this forum with more details with United-Mobile.
Hope this will help you.