I have been a regulated dude for 7 years. Started with cigalikes, then egos, then regulated boxes. Just got a wismec machina and love the heck out of it. I'm really into the simplicity of it, and how your build controls the power. My question is, what's the difference between this $40 mod, and the metal tubes I see for $400? Can something work better than this thing? Thanks for your answers.