Finarea S.A. is a Swiss company that operates discount phone services under different brands. Even if you are in VoIP, you probably never heard Finarea until now, but brands such as voipbuster, voipstunt are probably very well known especially if you are after deals to international calls.
Betamax GmbH & Co KG is a German company that according to their press release, in December 2005, they took over all of the VoIP services previously run by Finarea SA. A few more VoIP services were added after that to the group.
The rates and promotions are always different between these providers. The following table lists the rates with Romania as extracted by the guy at http://backsla.sh/betamax.
Other source of non-official but good information about these companies can be found at Wolf’s pages.