Best Strategy for Voice/Text/Data - 10 days between France and Germany

[inquisitor]

Originally Posted by Guthdog

1) Is there one carrier that I can purchase a SIM from that would provide satisfactory service to both countries? I doubt it, but I had to ask.

As you anticipate the answer is no, at least if you intend to call outside the EU or need data.

2) Who are your favorite carriers for quality of service and coverage for France and for Germany, (assuming that I will have to change carriers during the trip).

As long as you are not a heavy data user who needs omnipresent 3G coverage any operator will do it. Compared to the US coverage gaps are nearly inexistant in Europe and will usually only occur in remote uninhabited spots (see Mobile World Live - Coverage Maps for coverage maps of both countries).
Since I evade travelling to France due to prohibitively expensive data tariffs I can only provide advice for Germany, for which I would recommend Lidl mobile which provides best value for voice (calls to the US cost 9ct/min) and data (€ 2/day for unlimited data). Otterbach as well as Frankfurt are covered by O2's 3G network on which Lidl is based.
For further info on Lidl see LIDL mobile - Prepaid Wireless Internet Access and the corresponding threads on this forum.

3) Where should I acquire the SIM's, or should I leave this question for the concierge at my hotels?

At a Lidl supermarket.

[Guthdog]

Thank you for the suggestion Inquisitor, I appreciate it.

LIDL is not one I had seen in my searches yet. I am headed over to look at the link now.