Interview with Charlie Collias of Zylight about their new LED fresnel. I think what's really noteworthy about this new unit is that it really seems to be an effective workhorse fresnel, but it's not a big bulky housing- it accordions down to a pretty low profile in full flood for packing and moving. The accordion design struck me as both innovative and intelligent.
This unit also has a nice hard-edged shadow on the beam; it gets away from the mushy multi-shadow thing that is such a hallmark of LEDs. Remote controllable, daylight balanced, battery-powerable, this light looks like it may rise above the new pack of LED fresnels.
An associate of mine at B&H was predicting this one to be a big seller once it's in wide release.
Downsides?  Regular tungsten fresnels are still pretty cheap to buy and rent.  Until Electricity and replacement bulb prices rise up a whole lot more, I don't think there will be a wholesale adoption of this unit by the general rental house market.  It's a little pricey still compared to tungsten, about 2400$ for a unit that compares outputwise to a 650w fresnel.  Being daylight balanced, though, it compares favorably to the small HMIs on the market, especially when you take the replacement bulb costs into account.
Overall, I think this light will be a winner for smaller productions where the production company or DP owns a lot of the gear themself.  It's portability and versatility appealed to me for that market.

review and interview by Tom Guiney Airboxlights.com