Looks like a super-deal. I bought the Bosch impact driver after trying
out just about everything at an Axminster trade show. All the pro-
brands were excellent - makita/bosch/hitachi/panasonic - with little
to differentiate them, I bought Bosch simply because I have other
bosch 14.4V kit.

You sound like you do a lot of decking work, in which case you'll
probably find you use the impact driver 80% of the time, and have the
drill set up just to do pilot holes where necessary.

As others say, pozi#2 bits get broken a lot, though I think I've only
ever broken 2 pozi#3 bits. If you can possibly favour using pozi#3
screws (I use screwfix 6x80mm turbogold mostly), the problem more or
less disappears. I've yet to break a single Wera pozi#3 diamond bit.

Best combination I've found is the Wera rapidaptor and their diamond
bits (maybe the expense of the bits makes me more careful). I've been
a bit disappointed with Wiha stuff (quality superb, but bit more prone
to breakage) and with the iron bits from Wera (which the rep told me
were best suited to impact drivers) - in practice they've been most
prone to breakage.

I've yet to hear anybody that got an impact driver say "bit of a waste
of money"or "didn't use it much". I find screws are sufficiently cheap
and quick and easy to put in with an impact driver to make nails more
or less redundant in many applications.