I have 1 site but I need 2 domains (because of cyrillic to latin translation). Is it better content to be on 1 domain and the other to do forwarding, or is better to get same content on 2 domains?
You should use one domain to house the content, the other can just be 301 redirected. Having the same content on two different domain names can be considered as duplicate content. Your always better off 301 redirecting one to another.