I don't think you'll have any problems. The EPG subscription site lists 60 German Speaking channels that you can setup on the EPG. The Pronto itself is completely customisable using the ProntoEdit software, as long as you're happy with English menus on the ProntoEdit software itself.

I don't think you'll need a converter either as the external PSU supplied with the iPronto handles 100-240V, 50-60Hz. All you will need is a power cable to plug into the PSU, which is the same kind of lead that plugs into a common PC or Monitor (A kettle-lead as we call it in England).

I ordered mine from Bluedo in the US and cannot recommend them highly enough for efficiency and service. Warranty may be a problem, but posts on here suggest that Philips have said they will honour a US warranty in Europe.