That depends whether its domestic or international. I found that generally, on domestic flights within China, you won't get a word from the cockpit. It's the FAs who do the talking and the announcement. Not that it made much of a difference, since most of the time you won't understand a word of their English anyway.

But for international flights to-and-from China, the pilots will say one or two things, nothing special or out of the ordinary, just the usual "hello, thank you for flying with us" standard speech. So I don't think there is a huge difference either way.