The thing that keeps me from even considering the heatbit is that you can't point the miner to the pool of your choice. They claim they will be adding that functionality but as long as that is 'still coming'...im out. A huge part of the reason one should participate in mining involves the freedom to choose your pool or method of hashing for the next block.
Consider an s9 with fan upgrades. you could follow this guide less the case (https://www.cryptocloaks.com/the-future-of-space-heaters-s9-bitcoin-asic/), and you will have an s9 that runs between 40-50 decibals. It's kinda the equivalent of an exhaust fan in your bathroom or kitchen being on. Get creative with some DIY casing around the s9 and you can get it even quieter. I suppose though if you were ready to buy a heatbit, might as well splurge on the case from cryptocloaks too as it helps with the decibals and aesthetic.