As daft as it sounds my favourite at the moment is a £20 off eBay Chinese job that I wrote a seriously critical hatchet job on this website.
Found water getting in so fitted a waterproof switch.
Tried it with 4 Panasonic Ultra High Discharge (yellow tops) and blew everything, driver circuit and LEDs.
Fitted new T6s, all six of them, and got a better driver board with an inductor off FastTech for about £4, now a fairly good torch.
Now it doesn't nosedive faster than the batteries deplete.
My avatar is a poor likeness.