I was just about to order a German SIM card. It appears I have three options: O2, T-Mobile or E-Plus. E-Plus seems to be the least expenive on calls to the US. Any advice on which of the three is best would be appreciated. FYI--I have an account with Callback World.

Not sure what your definition of 'best' is. I have a phone that I use in Germany that is E-Plus. Coverage seems fine and it's always easy to find the pay as you go cards. I use my company provided MCI card, so I call a toll free access card and the cost of the call goes directly to the MCI card (and the rates on that, I can tell you - are absolutely absurd!!)

It doesn't matter which you get if the prime purpose is calls to the US via callbackworld.....you will pay the same thing anyway you go...

You can compare tariffs on www.prepaidgsm.net.....also you will find some people from Germany there on that forum who might give you a better answer than on this forum (although logos is pretty good on this and always has good advice regarding German sims).

In the pre riiing days I chose to go with vodafone de not for any particular reason..when in Germany I make very few local calls anyway but

1. Vodafone DE does allow you to set the voice menus to English (this is different than selecting English for the phone menus)

2. Vodafone DE can be kept active by purchasing vouchers in other vodafone countries and topping up that way.

3. Now with Vodafone Passport, Vodafone DE is somewhat useful for short periods of roaming say to Austria where you can continue to receive calls for free with only a 75 euro cent surcharge per call (not per minute)....

But others will probably be better able to help you.

By "best" I meant best coverage and quality of calls.

If you're looking for the best coverage, T-Mobile and O2 are generally slightly ahead of Vodafone, E-Plus comes in last. But there isn't really that much difference. O2 has a roaming agreement with T-Mobile in rural areas. Roaming is free of charge. So basically O2 is 1800Mhz in town, 900 out of town. T-Mobile and Vodafone (almost) only use 900Mhz, don't buy those cards if you lack that frequency. On the other hand o2 only has 1800 mhz coverage in town and suburban areas. If you lack 900 Mhz, you won't have O2 "coverage" (=T-Mobile roaming) in rural areas. E-Plus uses only 1800 Mhz, coverage sometimes isn't perfect out of the cities.

SIM cards for E-Plus are cheapest and start from 70ct !!!! (without calling credit on Ebay including shipment, any card you buy should cost less than 10€ with 5€ credit included.

E-Plus started using better (EFR) voice encoding years ago on 1800 MHZ, the other companies have followed. So there isn't any noticable difference right now. WCDMA mobiles have the best audio, but they are normally not available outside of Europe and Japan. At this moment WCDMA access is included only on newer prepay cards from T-Mobile. So a really coooool thing would be an unlocked WCDMA mobile and a T-Mobile prepay SIM. ;-)