Is this the new manual bit holder? It seems smaller than the original one - I would have preferred it to be bigger. It (obviously) doesn't need the centrotec chuck. In my opinion that's a slick setup.
I don't like the older Wiha type, much too bulky. The handle's too thick and heavy, and the centrotec chuck on it makes it even heavier and unbalanced. I haven't had my hands on the new one yet, but I bet this one's much nicer.
That blog has some detailed info.
Here's the official link to the handle, which makes me wonder about other hidden pages on festool.com:https://www.festool.com/accessory/200140---sd-ce-drive-uni
Inserted bits indeed have some play. The magnetic bitholder is an upgrade to the previous version.
Does anyone know the part numer of the previous version (bigger handle from Wera and black bitholder)?