Freebuzzer callback service from Voipax

Today, I received a lengthy advertorial in my inbox about a VoIP service called Freebuzzer, offered by Voipax GmbH.  I'll save you the fluff and quote just the relevant bit:

All you need to make free calls on your PC is your computer and your internet connection. Then start enjoying free international phone calls immediately by going to www.freebuzzer.com and entering both phone numbers. Freebuzzer will then call both parties and connect them totally free of charge.

Freebuzzer offers free phone calls to more than 40 countries in the world. The amount of calls is limited, but it's still a good way to make a quick call to your friends and family all over the world.

They aren't clear about the limitations, so try at your own risk.  This will also use up incoming minutes, so it's not totally free if you get charged for those.  Anyway, if you do check it out, be sure to leave a comment and let everyone know how satisfied you were with their service!

UPDATE:  Seems calls are limited to 2 minutes each.  Does anyone know if that's accurate?  If so, that pretty much kills any appeal this service may have had.