I have comparison tested the LW3000 & 4000 along with the Tektite 300. All three are excellent lights but my favorite standard size LED light remains the Tektite (Expedition) 1400. It is significantly brighter than both Lightwave models as well as its sibling the 300. It is also much smaller and lighter than either Lightwave in addition to being waterproof to great depths and having the most comfortable and well designed lanyard in the business.
The "two handed operation" mentioned in the reviews is caused by double O rings on the unlabled "Deep Dive" version of the Tektites. My Tektites have single O-rings which provide more than adequate waterproofing for normal dive use. If these are kept properly siliconed and the rubberized bezel cover removed then one-handed operation is comfortable and convenient.
My Tektites predate the addition of a fresnel lens as well as a bezel cover, and I can only assume that the lens has made a first rate product even better.
One other advantage of the Tektites over the Lightwaves is the noticeably whiter beam color as opposed to the Lightwaves' stronger blueish tint.
To sum up: The LightWave 4000 is the undisputed champ in terms of bright runtime. The downside is that it is an unusually large, heavy, cumbersome light with an inadequate lanyard for its weight and a noticeably blueish tint to its beam.
The Lightwave 3000 is a comfortably downsized version of the 4000 with very good brightness and runtime, but still blueish and inadequately
"lanyarded".
All three 3C TekTite models (there is also the 1900) are significantly smaller and lighter than the Lightwaves, strongly built, waterproof to considerble depths, easily operated with one hand (single O-ring version), have pleasantly white-tinted beams and come with a super-comfortable lanyard. The 1400 is brighter than even the LW 4000 for the first 2-4 hours and brighter than the LW 3000 for about the first 7-8 hours. After that the LightWaves slowly pull ahead, with the 4000 outlasting the other lights by a significant margin.
I would only use the 4000 for very extended expeditions or emergencies. For almost all other occasions under about 8-10 hours I would use the TekTite 1400. Of course the 1400 can be used far longer than that, but after about 8-10 hours the LW 3000 will be a little brighter.
Brightnorm