One of my sites gets its traffic with obscure rare keywords. That traffic is untargeted and my site currently gets 1.08% CTR. My other similar site in Spanish has CTR 2.56%. What do you think is it OK if I have untargetted traffic? What is OK CTR for targetted traffic? Some gets 15% and some gets 0.5%?
There is nothign like good CTR. Varies a lot with the nature of your site, and lot of other factors. My forum gets less than 1% CTR, while another site gets 4%-5%. You will be the best person to decide, knowing the cost of getting traffic in both cases.