Not used the Genesis, but have used the Holy Moses. Del, the guy who runs Four 4ths is not only a very nice chap (lent me a light to use at Mayhem when mine didn’t want to work for some reason), but he knows how to make a good light.
They’re VERY well made, better than anything else I’ve seen I’d say (including Exposure which are also very good), they’re easy to get spares for as he keeps them all in stock, the Holy Moses in particular is ridiculously bright and probably has the highest lumen to £ ratio excluding the cheap DX lights etc.
And like I say, he’s a real nice bloke. If you’re at an Endurance race any time soon, look out for him and his team, I’m sure he’ll let you have a play with a light.