I have seen mixed review's on their customer service, So I thought I would share mine. I have a new m555 cast frestanding and been having issue's with smoke smell's in the house.The factory rep for my area came out yesterday and went through the stove top to bottom and found a couple loose bolt's and put it back together but it still did not fix the problem. Long story short it was the pipe leaking even though I siliconed and taped all seam's, I have a defective piece of pipe. So he recomended that I ditch the Simpson duravent and switch to ICC brand pipe,then he tells me he is going to sell it to me for his cost I was expecting this guy to tell me it is a pipe problem and he is not resposible for A pipe issue and he is only resposible for the stove issue's but he steped up to help me out.