There are many possible reasons for choosing whether to publish in a 'traditional', reader-pays, journal or an open-access, author-pays journal, and for choosing between the latter. How much role do publication costs play?
From my personal experience, manuscript that had been submitted to an author-pays journal would be more likely to be under review so that I could have the chance to receive reviewers' comments which were helpful to improve the manuscript.
In this sense, author-pays journal is a good choice for early-career researchers, especially those whose English is an additional language.
A good point, which I had not thought of. But although you don't have to pay until after acceptance, the US$1500-2000 many charge is lot of money, not just in China.
Agreed on both points (Dr Ji Zhang's and Dr Corlett's).
I go for the free one but indexed. If not available, for paid one but indexed. It depends also on the quality of my papers. If there are only case reports (of course with possible low or no citation), spending a lot sometime is not worth it.
The maximum I have paid was US300, and that one was using grant money.
That's pretty much what we do here, since the Chinese Academy of Sciences insists on journals with impact factors and I don't usually have US$2000 for a high-impact open-access journal, but obviously a lot of people do!