Output is great on the mini 123 or using 14500 in the AA model, size and weight are great, look is great when it develops a patina of scratches in your pocket.
Threads, however, are not so great. Very gritty. As another titanium Mini owner put it, "like fingernails on a chalkboard". When I received it, the light had metal shavings in the threads already. Titanium filings continue to build up in the threads over time from use. The metal seems to have galling problems. It gives the impression that the threads are wearing and will eventually wear out. Maybe titanium is not the best material for a twisty.
Also, the fit of the threads is very loose. To give you an idea, I also have a Maratac Stainless AA which is almost an identical design. On the Maratac, if you loosen the head 90 degrees, that is enough that if you push on the head or fiddle with it, the light will not turn on.
The Quark Mini Titanium AA, on the other hand, has to be loosened AT LEAST 180 degrees to keep it from turning off. If you loosen it only 90 degrees, the light can be turned on either by pressing in on the head, or even pressing sideways on the head. I have had the light flash on in my pocket many times. 180 degrees feels like a long way to turn the head if you are trying to use the light 1-handed.
I generally can't operate this light reliably with 1 hand due to the loose sloppy threads, the gritty friction turning the head, and the fact that the head has to be tightened pretty hard to get a good connection (if you don't tighten it enough it flickers on and off sometimes).
The Maratac in comparison can be operated with 1 hand.
I have the quark mini titanium in both cr123 and AA versions, and the cr123 version seem to have less issues with the threads, but everything I said applies to both, just to a lesser degree on the 123 version.
That has been my after EDC-ing the titanium Minis for a month and a half (so far).
