I think a reasonable summary is that the homemade versions are cheaper and actually more effective than most commercial versions, with the downside that they ar

I think a reasonable summary is that the homemade versions are cheaper and actually more effective than most commercial versions, with the downside that they are usually larger and often noisier. The largest factor for effective air purification is airflow, and the homemade versions offer higher airflow but at the cost of greater noise and looking janky. There are somewhat reasonable fears that the homemade versions might be fire hazards, but in practice they are probably no more dangerous than the bare fans on which they are based. Really, both solutions work just fine. If looking commercial, be sure to consider the cost and availability of replacement filters. If considering DIY, realize that you don't need to get it perfect, almost anything is better than nothing.