Not really had chance to test it properly yet and I will follow this mini review up as I get the chance. Let us start with the bleedin' obvious. It is bright! I don't think it is overwhelmingly so, but the quality of light is superb. The beam is very even and without any hotspot, making it something of a beauty in use throughout the focus range. Absolute range isn't seemingly that great and as usual the LED Lenser figures are let us say, "optimistic" to say the least. However, to better it with an LED Lamp you are going to have to go for something more specialised, like the Olight SR90/91 Intimidator, with 2200/1500 lumens and a 50% greater price tag. Even then you will lose the ability to change the focus, as it is a fixed (though superb) beam and has a central hotspot, though I would imagine that this will have a 40 or 50% greater absolute range. Let us face it, the X21 at 950 lumens constant output is only now an upper mid range torch. What I can tell you is that you would be very unusual if you didn't love the X21 for it's output, but when it comes to cost versus performance, only you can decide whether it fits.
In use, it is a pussycat. Not as heavy or unwieldy as you might imagine and well built. The only niggle that some users report, concerns the switch, which is easy to inadvertantly operate. If you do, you will know about it, but if it is placed in its protective case, it isn't too hard to goof and leave the torch accidentally switched on. Moral here, is simple. ~If you are going to store it, remove the batteries first.
I do like the X21 and in fact have one on loan, whilst I await the hopefully imminent release of the rechargeable and higher performing (1500 lumens peak) X21R. In use, it feels to me, to be a highly portable spotlight instead of a torch. It will certainly give you an outstanding torch if your surroundings are dark.(as opposed to nightlit)
Finally, a word about Ledco. They are the UK distributors for LED Lenser and so their products advertised here are infact the real Led Lenser. Hope this helps a few of you and I suppose you can always get in touch with me through Amazon if I can help further.
Update July 2011
The main essence of the review remains as is, but I dumped the X21 and went for the Olight SR90 and am afraid to say that it leaves the X21 for dead in all areas. With the push on diffuser fitted, it has a very pleasing and wide flood beam that is every bit as usable, (and even at low power has close to the output of the X21 at high power) but when the diffuser is removed and the torch switched to high power, you almost feel the recoil and the X21 looks very, very second rate. That said, the X21 will please the majority, but I personally would never go back.