David wrote...
On the screw driver setting, even at the _highest_ torque
setting, I can stop the shaft turning just by holding the
chuck with my hand.

That is broken or at least not good enough, or you may have it on the
highest speed which allows momentum to build to overrun the clutch.
For screwdriving you should use speed #1 (at least for plasterboard,
cement board, rubbishy pine).

I have a Makita 14.4V 6337D.
I actually bought the body (£32), NiMH battery (£40), multi-charger
(£19) as odds-n-sods on Ebay as I disposed of other stuff. It is a
Marathon motor drill which does mean it has very torque, and uses NiMH
(or NiCad) batteries. It is a 2-speed drill and not a combi drill like
the MXT Combi which is about £45-55 for the body even on Ebay (and
heavier).

Set to screws, gearbox speed 1.
With clutch set to 5 it can be stopped with a firm grip, albeit giving
your wrist a good snatch.
With clutch set to 16 you can forget stopping it, it will actually
break your wrist before you can get the trigger fully down.

The downside is under part-speed, very high resistance, the speed
control can smoke and fail. I suspect that may be the run-in NiMH
battery. So I have a "no speed control" for brickwork and a "do not
abuse" for precise (cough!) woodwork. Makita would not entertain the
warranty because I had bought on Ebay, no point shipping it around and
just bought a replacement 6337D body for £27 delivered in the
recession.

Now, when I tried 12V non-marathon & 14.4V non-marathon with NiCad I
did find them weedy - even compared to an old 9.6V NiCad which I
suspect re 1998-2000 had a "marathon motor or its equivalent back
them".

Batteries do take time to run-in and achieve a full charge, but I find
1.3Ah is that bit too small - 1.5Ah is noticeably better in that you
can actually finish a job without finding the thing grinds to a halt.
On the NiMH you have almost consistent fresh-charge power until the
last 20secs, it really is that good. The downside is the self
discharge is pretty dire.

If you do not need a Combi, buy a non-Combi cordless with occasional
masonry (Bosch Multiconstruction bit) and a proper mains SDS for
masonry because nothing matches it except the expensive cordless SDS
drills (£200+).