[Bossman]

I am using globalsim (the one from freeglobalsim) and I am very satisfied with it. The sim itself is free, you just pay for the credit. The call quality is very good and all calls have completed sucsessfully. You get an SMS after each outgoing call indicating the cost of the call (it can be disabled), Checking VM is free, and the number can be forwarded to any number. SMS cost varies depending on country though. You can forward, disable/enable VM, check VM, topup, etc. from the website. Most of these functions are also available via the phone at no extra charge.

It needs to be topped up every 6 months though. The list of free incoming countries may be limited for some, but it's good enough for me. And, outgong calls cost in these countries are not bad at all.