All listed VOIP provider is best but I would recommend CallHippo because it's cheaper then ring central and having all advanced communication capabilities like call recording, call forwarding, IVR, on hold music, voicemail and so on. and their support team always available to help you. callhippo.com/...
I agree that, all these VoIP providers are in the market for a long time and have been providing some great services for businesses but i would recommend CallHippo. They offer most reasonable services with advanced calling benefits. callhippo.com/...