The great thing about CDAF is that when it gets it wrong, it usually gets it totally wrong. When PDAF gets it wrong, it gets it a tiny bit wrong and unless you review immediately you may not realise until it's too late. I'd relate the story of trying to get the in-camera focus micro-adjustment sorted on a Sigma 30/1.4, a Canon 50/1.4, and a Canon 100/2, or knowing that the same lenses may be virtually unusable at larger apertures on a camera body without micro-adjustment, but I don't think that swearing is allowed on this board.
Well don't wanna argue =] but is true. AF on my GF3 is noticeably faster than GH1 specially with the new lenses, but still GH1 got a speed that never actually make me feel its an issue of any kind. Its not fastest according to the current standards, but is always fast enough.
Still a good article for getting some insight know how.