Initially, I was planning to use metal pipes for the exhaust fan pipe in my second bathroom, like I did for my other bathroom. However, the cost seemed pretty high, so I decided to try another route and use flexible duct instead. I heard that as long as it's insulated flexible duct, it should work fine. The installation wasn't that hard. You just need to have good metal shears to cut it to the size you need. However, there were a few alterations needed in the shape, but it wasn't really a big deal. I think the insulation is helping with soundproofing the air exhaust sound a bit. Overall, I think it's a decent product.
Dobeman 
