This is just a question, as i have a hard time letting go one of my watches.
I got a Certina with 25-66 movement and a Volna with a 2809 Vostok movement.
Both movement are in equal shape (very good) and top serviced.
Speaking only from the movement point of view and considering that they are in very similar state, which you consider as being the better one.
I know its a strange and dumm question...