I just picked up a 3D 3rd Gen for about 48 at Wally World.
So far I like it.
Comparing it to my old non-D serial number 3D maglite Ive noticed this.
It is very light in weight by comparison.
Empty the OLD 3D is 508g
Empty the 3D 3rd Gen is 332g
The new is about 1cm shorter than the old. I didnt have a ruler so that is an eye-ball guess. Id say a little more than the thickness of the tailcap really.
The body is thinner. Its noticable to me. It will still fit in the regular D-mag mounting brackets, but nowhere near as snug. It seems to hold,mounted viertical or horizonal but i feel if its not mounted on a non-stationary object, like in a vehicle instead of on the wall in the home, there is a slight chance for it to slide out of its brackets in certain mounting configurations.
The button is smaller and its no longer a clicky button but a regular push button.
The head focus feature has changed as well. Instead of making full rotations the head only moves less than a 1/4 turn for the focus range.
The multi-mode-multi-level feature didnt take much time to get used to either.
The stobe function definately a stobe. Its almost as fast as a strobe light youd find on a Djs equipment shelf. And I like the momentary light function. The comes on if your finger is on the button. Its nice for quick point-n-spot usage.
I guess now is the ultimate test, seeing how it holds up to time/use/abuse.