With the set you should be mostly fine. 1/4-shank ball detent bits fit into the eccentric chuck if you're really concerned about using them. I sprung for the locking bit holder 492 648 because it does a good job of holding the regular hex bits that fit into the magnet bit holder in the handle, as well as ball detent stuff.
I bought a small set of centrotec drill bits. They work ok, but I don't think they're good enough to justify the added cost. That, and they were made before the bits could be replaced, so now that they're dull they're really not much use. I'm sure I could sharpen them, just haven't really needed to with all the regular bits I have lying around.
That said, I do waffle back and forth on the topic of the collared countersunk bit 492 523. It's tempting, and I see the merit, but at $65, I'm still on the fence. I have a depth collar for my existing countersunk, so I'm not really sold.
I do own the screw gun chuck. When I needed it, it worked great. But at $105, I'd wait until you really needed it.
