I'll avoid the parts of the debate about adaptation, whether or not size matters, etc. At first when I read mark's stuff about sheer stress caused by the stir bar I didn't think too much of that. But after trying it, to me there is a distinct difference in aroma between my stirplate finished starters and the few oxygenated non-stirred high krausen starters ive made. The oxygenated non-stirred high krausen starters smell fresh and tasty while the stirplate ones have a (for lack of better term) bitter, trub-like, unappealing aroma. Whether or not the cause of that off aroma is sheer stressed yeast, or even something that means those yeest are not as good, I don't know. But there must be something different, or they would look and smell the same. Couple that with my experience now of 4 consecutive batches taking off sooner and more actively than I am used to with stirplate starters, for me thats evidence enough that oxygenated non-stirred starters are the better way to go, for me.