BISSELL Air320 Smart Air Purifier

I really wanted to like this air purifier. Great styling, high volume, decent price, carbon filtration for odors. However, there is a quality issue with the fan that the manufacturer won't address, despite multiple reviews on the site and my own experience. It's also not designed for smooth, quiet airflow, which is more important than looking nice.The short version is that they replaced a lemon with another lemon, ignored everything I said about the problem, shipped a replacement filter to an address that can't accept FedEx, then said I couldn't get a refund on the "5 year warranty" because I purchased on Amazon. Amazon generously accepted a return after 3 months, thank goodness.It also has some design flaws other than the quality issue causing the fan to rub inside the case. The design ignores principles of laminar airflow and this makes it noisier than comparable models (including my old Hamilton Beach from 2004). The front "speaker grille" is a fabric-covered grille that picks up enough lint to make the airflow uneven and noisy but not enough to keep the HEPA filter from getting covered in fibers from clothes I'm drying indoors. The array of perforations at the air outlet is attractive but not conducive to quiet laminar airflow. I suspect the interior of the cabinet isn't contoured for laminar flow either, and the turbulence is noisy above speed 2. It's relatively quiet on the lowest speed, until you get some lint on the prefilter grille and the fan stutters. The uneven sound draws more attention than a constant flow. You're supposed to brush the fabric prefilter--have they ever talked to their major target market, people with allergies and asthma? We just bought a machine to pull all this stuff out of the air, and now we're supposed to brush it off the front where it's going to get all over us and up our noses?And after I cleaned it, it would make a loud mechanical whine after I restarted it. That's the quality issue I finally returned it for, because it just wasn't working right. At least one customer has reported this escalating to the machine overheating and smoking, yet Bissell won't address this potentially hazardous condition.The whining noise on restart was separate from the loud airflow noise on speeds 3-5 and very distinct at the lowest speed when the airflow is most quiet. At first, I thought maybe the filters got out of alignment when replacing the prefilter (which snaps on the front), so I tested by briefly running the unit without the filters. No improvement, and it clearly came from the fan. My best guess is that it is off alignment and rubbing on the inside of the case. The noise faded out after running the unit a while (properly with the filter) but recurred any time I stopped and started it for cleaning. The noise eventually didn't go away, and I was coming up on the 1-month return period, so I called Bissell tech support.They assured me they had no idea what it could be, after I told them it was NOT the loud airflow on higher speeds, but they would exchange for a new one. The new one had the same problem. They said they could not exchange a second time or refund because I'd bought it on Amazon, not directly from Bissell's website. They said they had never heard of the problem, even though there are over a dozen reports on Amazon addressed by Bissell's social media team, and one overheated and started smoking. This was really annoying because it felt like gaslighting--though it's probably just that the company is big enough that the social media team doesn't report reviews of quality issues to the QA/QC team or Engineering, let alone to the CSAs answering the phone. They clearly don't investigate issues with returned units--mine is probably in some other customer's house now--or they would have figured out that this model has a quality problem and solved it--even done a recall.Part of the problem that made me mad enough at Bissell to want a full refund was that even after I told them the noise was unrelated to the filters (I could hear it with them removed) they insisted I had managed to fill up the HEPA filter in only a month and they needed to "troubleshoot" (aka stall me until it's out of return period) by shipping new filters. I figured I wouldn't turn down a set of free filters, but I never got them because of shipping problems. I told the agent I can't receive FedEx at my apartment (another long story) but she said she can't have it shipped to a FedEx location because it HAD to be shipped to the warranty address. She assured me I could change this on the FedEx website once it shipped. Well, no, they used FedEx SmartPost which can't be changed by the customer. I spent about 2 hours on hold with FedEx and Bissell with each one saying the other one is responsible. I finally gave up, hoping that "SmartPost" meant it was delivered by my USPS carrier like some UPS/Amazon shipments. Except it isn't! And FedEx marked my filters Delivered as he left the truck, because that's easier than doing it at my apartment--but he argued with my apartment manager and got kicked out before he could deliver anything. After several calls to Bissell, they agreed to reship to a FedEx location--but a week later when I called to follow up, they said "No, it was delivered last week, we are not going to send you free stuff" and said there was nothing about it in my file.At that point, I gave up on dealing with Bissell customer service. Two lemons, no awareness of known issues, multiple incidents of agents refusing to believe me and not documenting the conversation in the file--this is a terrible business relationship. Although there are some nice features on this model (the digital particle counter, auto-dimming display, attractive case) there are many other options on the market. It's eventually going to fail, possibly catastrophically with smoke that sets off the fire sprinklers, and they're just going to BS me.