The original language will almost always sound the best and in the case of anime, that's Japanese. The Japanese dub will be what the lip movements are synced to and the actual studio making the anime will be involved in choosing and directing the voice actors to best match their vision. Foreign language dubs will be made by some third-party companies with little to no involvement of the original studio.

I have a feeling that the people who could judge that best probably aren't present in an English language forum.

I think if we look at the spectrum of popular international animation with South Park America on the low end and Miyazaki output at the top, the care put in to make the spoken word match lip movements often correlates to where you are on that spectrum. And there is a lot of stuff trending towards the low end. They probably don't do 20 retakes on a line read during voice recording. No matter what language they are doing.