V570 owner here. Listen to the poster ahead of me. If picture quality is that much of a must to you, the V570 and the V610 are not for you. In fact, you stated no reason as to why you are interested in those models.
Now, about the V610, it basically offers a long zoom compared to the V570's wide angle. But otherwise, they're very similar cameras.
P.S. I love my V570.