I have a Bebob LUX LED40 Fresnel LED:http://www.prokit.co.uk/index.php?view=product&product=Bebob%20LUX-LED40
It has a fairly crisp beam with some control over beam spread. Mine runs off a V-lock battery (with mount built in) and has a good throw- like a hand held light cannon. It is dimmable with no flicker that I've observed. It isn't a complete replacement for a Tungsten Fresnel, but it does most of the job.
As is the nature of discontinuous spectrum sources like LED lights, the only real way to tell is to test it yourself with your camera set-up and mixing with your other lighting. The one I have is daylight balanced, and works well mixed with real daylight when shooting on my Panasonic AF101, HVX200 or RED Scarlet.
Gelling it to tungsten is a bad idea- you get unpredictable results with green/magenta colour shifts depending on the exact camera, gel and lighting set up. So I only use it in mixed colour situations if I want a Xenon-like punch of blue light mixed with warmer tungsten or Gekko Kelvin Tile light panels.
What I will say is that I've found it fantastic to be able to shoot on location with a few Kelvin Tiles and the Bebob, a few V mount batteries and some kit stands- no wires, no mains plug, no generators- heaven!
Does anyone know if the Arri products or Photon Beard Light Emitting Plasma products are actually available yet?