I was originally after Pelicans when I got into Underwater Kinetics. I'm now so used to Underwater Kinetics stuff it would take a lot to dislodge me. Before I got into proper Terralux mods [TLE-5EX Ministar Extreme] I used a 4*AA Underwater Kinetics on land too 'cos it is about the same length as a 2*AA and only a bit fatter. The light output from it dwarfed anything else sensible around [yeah, I know there are those trendy things that burn for a few moments on Lithiums] and has that chuck it in a bucket true workmanlike aspect. And the Sunlight SL6 with two parallel stacks of 3*C cells is an 8 watt compact scorcher at a bargain price.
The thing that first attracted me to Pelican, apart from performance, was the amusing and famous guarantee with the exception shark bite, bear attack, and children under 4. I believe they are great kit, and if I was looking for something running on 4*AAs that attached to my mask for me it would be arbitrary between Pelican and UK. For a powerful compact blinder though the UK SL6 edges out the Pelican.
Note: I've not tried the LED UK and I wont 'till I know what they are like.