When I'm in Southern California I'm about equal distance from LAX and ONT and even with TBIT being a bit of a madhouse when BR15 departs I don't find traffic to LAX to be all that bad at night.

I'd​ be tempted to try this flight just for the novelty of flying out of ONT but I've never had the desire to fly CI. I met a CI pilot about a dozen years ago and was talking to him about CI and he told me when his wife and kids fly to the US to visit family he had them fly BR due to safety. That always stuck with me, even though I know things are much improved now.