Cree XLamp MC-E K0-WG 370~700-Lumen LED Emitter on 20mm Star Board (MCE-WG-K0)

Pros: Very white, very bright, very nice upgrade from single die emitter, especially CREE.
Easy to swap a 20mm CREE XR-E star with this MC-E star (if you can solder).
Star is aluminum for good thermal transfer. (Hopefully, emitter slug is soldered directly to aluminum star wihout thermally insulating PCB layer in between, but no way to tell without unassembling.)

Cons: Not all emitter leads were soldered together when I received it (see pic in forum). (Not a big deal, but a quality control issue.)
Unique power requirements (3.5v 2.8A in parallel, or 14v 700mA in series) make finding an appropriate regulated buck/boost driver difficult.
Has different focusing requirements than single die CREEs. Not as difficult to focus as an SSC P7, but still challenging, especially with collimator lenses or fraen optics.
Doesn't pull the full 2.8A of current expected. In fact, mine only pulls 1.2A of current from an 8x7135 driver that is capapble of delivering 2.8a.

Other: If brightness is more important to you than runtime, you will be very pleased with upgrading an existing torch from a single emitter star to this MC-E star, provided you can also supply it with at least 1000mA.

Pros: Super bright, great white tint, much easier to focus then P7.

Cons: Leads of emitter not all soldered together on receipt, but very easy to fix.
Thermal management definitely an issue. Must make sure that whatever you put this in is well heatsinked. My first one melted an acrylic collimator lens after 20-40 minutes and the dome came off the emitter from the heat.

Other: Probably the best upgrade you can give to any CREE torch that can handle the heat and power consumption.

Pros: Single chip so you need only one lens
Compact so it can replace XR-E
Massive white light output (4 times XR-E)
Comes on individual wired star that is thick so seems to be a good heatsink
Has very low Vf

Cons: Stated and partially made parallel - some of the pins came soldered together
Only bin currently available

Other: Great for own DIY projects or flashlight upgrade

Pros: Nice product. Mounted well to serial board although advirtised as parallel. Beautiful unit, if wired correctly it should shadow the P7.

Cons: Wrong format for me. Had to manipulate many things to accomodate this item. This is quite an inconvenience considering the time it takes to recieve from DX.

Other: Good product but DX is confused as to how these are terminated. Be ready for whatever shows up.

Pros: Bright and powerful. Pretty straightforward replacement for CREE XR-E, with small challenges to focusing and power supply.

Cons: 2nd set of boards I received were serial, not parallel. Had to scratch trace routes on board and solder together leads on each side of LED to convert to parallel.
2nd set had VERY green tint compared to nice white tint of 1st set. I don't think the LEDs I received in my second batch were K-bin or WG tint. : (

Other: powerfull emitter, fun for projects, but frustratingly fragilie at 4x the cost of XRE stars. A bit of a gamble quality/brightness/tint-wise.

Pros: Bright, price, nice board

Cons: Poor manufacturing, bad product description

Other: I ordered mine early, when it finally arrived, the board was designed so each die was addressable which is great for testing.
The solder on the star was horrible, the joints were connected to each other, and had to be resoldered to truely have individually accessible dies.
If you want a parallel setup, its easy enough to take a soldering iron and just join up all the joints on each side.

Pros: pretty bright
I made a household bathroom bulb with this and it works well inside a white batroom diffuser. Drove it at 1A Vfw is 3.9V glue to a cpu heatsink. I just use old transformer with resistor in series to drive it.

Cons: no cons other than it gets pretty warm. I'm using an old pentium M cpu heatsink to release the heat. It seems warm to the touch.

Other: Pretty cool for a household project. I would recommend to buy.

Pros: I bought this to replace the Nichia LED array in a popular 3xD camping lantern so it had a better tint and added brightness. The tint is pretty good (close enough to WG) although it varies toward the edge and centre

Cons: It was a bit tricky to solder the connections to make all 4 dies work in parallel because of the gap between the pins. I had to disassemble the lamp again as one of the dies stopped lighting up, maybe some wire would have worked better. I got this last year when it was on back order most of the time, took about 2 months to eventually get one.

Other: Easy available, fairly priced, in working order.