I've used this 'floss-action' head for a year or so now and, personally, I feel that they give the very best clean that I can get from my Oral-B toothbrushes (I have two, one for home and one for travel).
Basic information: They fit all Oral-B toothbrushes, regardless of age (see the compatibility for the ones that Braun say it will not fit) that I have and there is no 'special' fitting or anything like that.
The yellow plastic bits on the brush seem to really clean well between the teeth, but there is no difference that you can detect while you are actually cleaning.
I still floss once a week, but these heads seem to make that almost redundant.
So, in summary: If you dislike flossing, this might be enough on its own; if you want your teeth to really feel clean, this type of head is first rate.