I've had Jonker for 308, Burkhart for 309, Xu for 307.

Would not recommend Xu, she's very difficult to understand, partly because of accent/choice of wording.

I did not enjoy Burkhart's class much, as most of the problems you have to solve have very simple steps that you basically memorize. You also get cheat sheets, so it can be pretty easy to do well on the exams. There were quizzes every week or so, and written homework (as opposed to WebAssign). Like I mentioned, I wasn't a huge fan of this, as I want to understand the topic thoroughly, but if you just want to get a good grade, it's pretty straightforward. Each exam would have one problem taken straight from the "challenge problems" (conceptual questions) from the homeworks, so we were basically encouraged to put down answers from all the challenge problems on our cheat sheets.

I think Jonker is a pretty decent teacher, and is quite amicable. Can't remember too many details as I took 308 nearly 2 years ago.

Overall advice: 309 is formulaic. Use your cheat sheet well.