Sorry but a year after I chose Tropo over Twilio, Tropo still wins:
Twilio: "Twilio does not offer phone numbers from outside the US and Canada, and you can’t port international numbers to Twilio."
http://www.twilio.com/faq/international
That's my issue with Twilio too, I need UK inbound not just outbound - calling US numbers from the UK is (apart from with VoIP phones) pretty expensive.
Twilio: "Twilio does not offer phone numbers from outside the US and Canada, and you can’t port international numbers to Twilio." http://www.twilio.com/faq/international
Tropo: "We offer local numbers in the US and 40 other countries - here's the full list of available countries, note that these are also free for developer accounts" https://www.tropo.com/docs/scripting/international_dialing_s...