[inquisitor]

@kuba.g
Fonic SIMs can not be recharged by credit card, but only by topup vouchers or a German bank account.

@Kritiker
A disadvantage of solomo pro is, that the SIM is only available online and can be shipped only to Germany and few neighbouring European countries.

@dg7feq
I don't know where you or your company have been using the eplus network, but three of my friends recently switched operators because they had continuing enormous problems with data connections as well as with voice calls with epus. Two of them live in Stuttgart and one in Hamburg - they reported not being able to establish data connections and not being able to receive or place calls while their phones were registered on the 3G-network almost every day during the rush hours.
When I was an eplus customer from 2006-2008 the 3G network in my home town was so congested, that with a probability of 80% incoming phone calls would not reach me, allthough I had very good signal strength.
Problems may lessen if you switch your phone in 2G-only mode, but all in all their network still is a pain.