Pros: Nice and cheap, these little batteries come in a pack of two which is quite handy, for my flashlight (SKU 24354) these things have powered it for ~1hr fine without me noticing any dimming or diminishing of the beam.
They charge fine in charger i also bought from DX, with the two of them it's great for a single battery flashlight as one can be in the flashlight as the other chargers, you practically never have a time without a charged battery ready to swap with.

Cons: Theres nothing really wrong with these batteries, they havent exploded or melted or done anything violent. They power my flashlight fine and havent burnt it out.
Been using them daily for about a month and a bit and nothing has failed with them.

Bottomline: If you bought a flashlight and just realised it doesnt come with batteries (yes i did that xD) these are perfect, not too expensive so you still have some cash to buy other DX stuff.
These batteries are protected (have a regulator built into the battery, underneath the wrapping) so they won't go frying anything.