Lots of debate between the two types for sure, but I don't see much info where a 2.5lb extinguisher runs for 50 seconds, like the Element E50. It looks like the 2.5lb typically last around 10 seconds and 5lb are 15-20 seconds. You will get more time with the 5 or 10lb vs the 2.5 versions for sure, but the huge size and where to put it is a no go for me. New (although not really) and different ways to do things always create debate, but I definitely appreciate the fact that they do not expire, and leave virtually no mess after use, and are a lot smaller. When I spoke with Element about many questions and concerns, I was completely satisfied and have no reason to believe all their claims. They know what they are doing. Its virtually identical to the Stryker extinguishers so widely used in the outback and overseas, the US can just get the Element instead. I say get the best of both worlds. An E50 or E100, and a FEM from Wits End.