I got a CooYoo Particle L (same as MecArmy PT16). It had good build quality and a good feel, nice-ish LEDs, very bright, but the most awful UI I’ve come across. I ended up giving it to a family member.
Supposedly there are newer versions of the light with a slightly better UI but it’s impossible to tell what you are going to get so I just gave up on them.
My Cometa, not due to the quality issues even. I had fun modding one and tightening the zoom threads with JB weld, etc… Dropped new emitters into see how they looked… Then I realized, the zoomies are not my thing…
I bought two… Anyone wants two cometas for $50 shipped (US only) shoot me a PM. One is an XPL HI V3 2A and the other is a domed 219C 5000K 320 I believe… Trades are good too… I got to put a WTS thread up and clear the shelf…
I do not have any “let down” lights, but I have lights that are least used, because I bought them to add to my collection.
Non collection lights, for use: Two of my largest lights get used for my night walks, while my other large lights are less used.
ReManG, you have PM.
I’d but your mk1 but shipping from Greece to Canada probably won’t work (too costly).
Wellp, you may’ve found a buyer… 
I keep banging the same drum, but a twisty in your pocket or bag is nigh impossible to accidentally turn on.
I’ve done both to tail-clickies and side-clickies, more often than I’d like to admit.
Heretic!
Crappy innards, but with a nice solid brass pill from Fasttech, they still make great hosts for XP-E2s and other lower-power LEDs. Even the crap tailswitch can easily handle 1.5A or so.
Not exactly a 9.5 on the Richter scale of lumens, but holds the hotspot together nice and far for excellent throw!
Never tried dedoming an XP-E2, but that would probably kick…
Okay… biggest letdown? Gotta confess, my S2+.
Love the host, love the tint, really like the semi-floody beam for closer-in work, even like the spread of L/M/H, but that damned blink-on-low still drives me absolutely buggy. It’s a poke in the eye every time I use it…
And I’ve just been too lazy to take it apart and try reflashing it.
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L2? Beautiful thrower, but no idea what’s up with the sandpaper-finish anodisation. It’s really rough and chalky. It’s a bit unnerving.
My (Convoy) C8 is a gray matte-finish, yet still pretty smooth to the touch.
Other (clone) C8s are smooth and glossy… and black.
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Love the Jet II (regular, not pro), but I really wish it’d fit 18350s as well as 16340s…
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Aside from the S2+’s UI, they’re pretty minor gripes, so thankfully I haven’t gotten bitten too badly this year.
For me it was SingFire SF-348 - strange beam, pretty dim, feels chep. Tint is not great also.
PS. I love my Skilhunt H15 - agree that it’s a bit heavy and has annoying red blink, but…but besides that it’s really versatile and powerful (for AA) light. It has great balance between power/runtime.
Less used light is
Actually, it’s manker e14
Because the dome of leds flew out all the time
So it shows strange annoying blue tint
My biggest let down is Klarus G30.
It suddenly stopped operation while in turbo mode. The
flashlight was warm, but not hot. The battery voltage was about 3.9V per
each of the three protected cells. The flashlight did not reacted to
pressing of either of the switches. Upon releasing and tightening again
of the tail cap the light starts operation in some random mode, and it
does not react to the switches; the only way to shut it down is by
release of the tail cap. The mode it enters after tightening of the tail
cap is completely unpredictable.
I notified the Klarus customer service yesterday and awaiting their response (assuming that they will respond).
I think shipping will be double the price of the light 
My 2nd DQG Tiny 18650 IV - which died after 3 months - due to one drop from normal hand height to a wood [or concrete] floor - can’t remember the exact drop.
Became intermittent, then finally cannot be revived.
Took it apart, can not fix or find problem.
(The first one died when the switch failed 2 ways at once.)
Gearbest did give me half my money back, but still, I’m stuck now with the idea that 18650 lights just can’t be that small and cheap, and be reliable.
Now I’ve got a Manker U11, which is nice but way bigger than the Tiny, and an Astrolux S1, which is very nice, and the same tininess as the Tiny, but at the expense of smaller, uncommon battery (18350).
I’d rather just have 18650, 85mm long, plus durability/reliability for $30.
wle
Jetbeam Jet I MK, I only used it once. not pocket friendly light for being unintentionally power on when get stuck in your pants and when you need it battery drained out even the clip have a light grasp.
I don’t really have a letdown light of this year (unlike 2015 :confounded: ), thankfully, but I do have a minorly disappointing one that I’d nonetheless been using this year (on a ball cap brim when some lights at my workplace went poof), and that is the Olight S1. The runtimes are a joke on 16340; seriously, 63 hours on Moonlight is year-200X levels of inefficiency, and it only gets worse from there :person_facepalming:
Heh, I remember when the flashy on Low mode on my C8 used to drive me up a wall. I just got used to it, though – I don’t have any knowledge of torch modding, and have to practice a lot with a soldering iron before I trust myself to touch a flashlight with one. Also, parts are costly for me.
ADDENDUM: You can get it from Simon with ToyKeeper’s new non-blinky firmware for a very small price increase. Sounds like a killer to me!
For me it´s the Astrolux S41S XP-G3. Love the Manker made S41 Nichia which works flawlessly and has a great tint, but the XP-G3 tint is just … :confounded: PLUS all the hassle with the faulty head and now the problems with the driver (stepdown from turbo to moonlight). Host Looks nice, but get´s hardly used by me anymore.
Also, I retrospective I regret getting the ThorFire S70. Paid top dollar for it, and now after the much better L6 came out and with the S70S announced, the resale value has almost dropped to zero… might end up giving it away as a present, but with two 26650´s needed it´s not a “muggle light”…
K.
Fenix ld22
Has an outdoor and tactical mode and had the light switch between them in the pocket a few times.
Nothing like needing light and having to screw around switching modes around so you can get what you want. Shelf Queen!
Also the lumintop torpedo. Good light, just not practical for everyday use.
Not disappointing at all, but getting a lot less usage than I had in mind: Klarus Mi7. I was hoping it would be small enough for EDC in my jeans watch pocket, but it’s just a bit too long for that. And while the side clicky is nice, you’ve got to keep locking and unlocking it for pocket carry - annoying. Nice light overall, but just didn’t cut it for pocket carry. It’s too bad, an excellent light overall.
Biggest let down was my Haikelite MT03 by far! Got one of the duds that has less than 1/2 the claimed output and there is zero customer support. Other than that, I don’t regret any of my purchases.
My Astrolux S41 SS I preordered. DOA, contacted for a replacement head, and they claim shipped, but still haven’t received it. Meanwhile, I see all these people who have not only ordered the since revised S41s, but have actually received them.