I just received my first Titanium light - D25A Clicky. It's the 2013 edition, XP-G2. First impressions are that it exceeds my expectations - for a small premium on the aluminium version, I was expecting a fairly shoddy piece of work. It's not at all, in fact it is beautiful.
Some comments. There is a small gap between the body and head, even when tightened, and the brass shows. Still, that brass makes twisting the head very smooth, with no titanium grind.
The beam is as beautiful as Shelm describes - this is my first XP-G2 emitter, and I'm very happy.
The downside is a pre-flash on switching on in moonlight mode. Also, I tried many times to do the three times head twist to access the second series of modes, to no avail. Seems this light only have the one set of head loose modes (with more blinkies that I, or anyone else will ever need). Good to read hear of the one second trick to avoid these and reset back to moonlight (which, incidentally seemed quite bright - brighter than, say, a SC600 - but perhaps only because the hotspot is quite focused).
Anyway, after playing with the head many times, and going through the modes, I noticed that the pre-flash had gone. Great. Except that it returned soon after. I think maybe the mode changing had had some effect. At one stage, going through the modes in sequence, the low mode appeared, without preflash, but then noticibly dimmer after a second. Very strange.
I have it now set so that the pre-flash doesn't appear, but I'm pretty sure that it isn't a true moonlight mode, so maybe the head twisting, mode changing has worked.
Confused? Not as much as I was! It's still a really nice light, and bright enough on eneloops for me not to want to use 14500 (I did, briefly, and the high (head loose) is exactly the same as turbo (head tight).
Oh, and I haven't tried to get the tailcap off - doubt if I could without freezing etc.