The metal ones are a bit louder than the plastic ones by what i read. I have an Apollo Hort metal one from amazon, only 190cfm and just ordered a vivosun plastic one for another tent to compare(the metal fan has gotten a lil louder over time i believe, you can hear it from outside the room with door closed but cannot hear it thru the floor when ur above it in basement). I dont care about noise tho cuz its in my basement but interested in seeing the difference. Apparently vivosun has fantastic customer service so if you're unhappy with their products they'll give you your money back so thats why i went with them this time. And obviously with amazon u can always say shits defective and get free returns up to 30 days.
Ipower, apollo hort and vivosun all sell inexpensive grow equipment on amazon, i think there are others too but those r the ones i see the most. Im happy with my apollo hort. tent, ballast and fan. The cheap carbon filter sucked so i returned it and got a Phresh filter. The apollo light bulbs were crap too. So like anything you have to learn what you can buy cheap and what you can't, and sometimes it might just take getting a dud the first time and getting a good one the next time due to low qualitity control of the chinese stuff.
