Currently I don't consider
Ring.to to be a better choice. They are really the new kids in this arena. I do however expect them to grow and become a real competitor to Google Voice. I have an account with
Ring.to and I am beta testing the latest Android builds. They have come a long way in a short time. Google Voice however is concentrating their efforts on integrated messaging. For Google phone calling is just part of Hangouts. I don't expect a lot of innovation relating to the phone calling part of the service.
Ring.to on the other hand is concentrating on a phone calling application/service. The parent company of
Ring.to(Bandwidth.com) is actually one of the partners that allows Google Voice to operate. I'm also a user of their sister company(Republic Wireless).
I am expecting some great things from
Ring.to and I think there will be benefits to get in early.