I'd probably suggest that you go with the PopAds. Their dashboard is really good for beginners because it's user-friendly and quite easy to use. They have $5 minimum withdrawal over PayPal and also support wired transaction directly to your bank account.
I believe that they have the highest CPM rate. The rates, of course, differ on some factors such as your visitor's country, your website's content and more but judging from the comments that I've read through the years, people always praised it. They accept all kinds of sites, even adult content ones and this is why I think that they're superior to the two other options.