From my observations, Ch. 3 has better written scripts. Their lakorns aren't as draggy compared to Ch.7. In Thailand, Ch.7 is more popular in ratings. However, ever since Nadech and Yaya came into the picture, Ch.3 has stolen the spotlight and attracted younger international fans. That's why more people favor Ch.3 and its actors now. To me, Ch.7 has much more mature actors. But Ch.7 veterans definitely are not better than Ch.3's. Plus, they all retired already. Ch.7 has mostly newbies with an exception of Aum, Vee, and Oil.