My thoughts on the D10:
I like the continuous adjustment of brightness levels, though at maximum it's not all that bright; about equal to some $15 DX CR123 lights I've used.
I find it easy to accidentally bump the switch when the light is hanging in my pocket from a lanyard and I reach for my keys.
The lack of a momentary on (without having to twist, which defeats the purpose) hurts it for me. I'd prefer a forward-clicky, or for the UI to be modified so that when you hold the button down for more than, say, 1/4 second, it decides that you only want it to be momentarily on, and thus turns off when you release.
The brightness on alkaline vs. nimh vs. 14500 is impressive; they're all pretty close. I haven't tested runtime yet.
The battery and switch contacts look quite nice, and I doubt I'll have trouble with grime any time soon. However, the spring on the negative end of the battery chamber is nearly inaccessible, so if anything happens to it, repair would be difficult.
It tail-stands quite securely, even with a lanyard attached. The holes for the lanyard are a bit far apart, however, and thicker cord may rub against or interfere with the button.
It's a bit difficult to twist open, but it's not like it's a twisty switch, so that's not very important.
How come everybody's using orange o-rings these days? If they make them in white, that'd look great on this light -- the black HAIII is dark and uniform, and a white o-ring would contrast nicely....
...but that's an awfully trivial complaint.
The knurling is good and clean. I'd prefer some kind of anti-roll, but with a lanyard installed it can rest on that.
The NiteCore logo is on the head, and the SmartPD logo is on the body, and when it's tightly closed, they don't quite line up.
The above points may be mostly negative, but I'm generally very critical. If I didn't mention it, that probably means it met or exceeded my expectations.