Yeah I don't think there is any such thing as "overkill" when dealing with odor. While researching today I read a post where a grower said they would spend any amount of money on something that kept them out of prison, and I think that sentiment sums up this entire situation quite appropriately. I also have fabreeze plug-in scented thingies, scented candles, and a huge tub of ONA gel I like to bust out during the peak of flower.
For short term solutions (say if your parents or landlord needs to drop by on short notice) nothing beats cooking to cover up the smell of growing cannabis. I like to saute onions and peppers with some meat and spices, but bacon is the quickest/most effective for my money. If you have time, a crock pot full of chili and spices is great because your house will stink like the chili as long as the crock pot is running.
With my DIY I really needed those masking agents, and even then the stink tended to leak beyond my walls. If I can eliminate 99% of the odor (which is apparently what MountainAir claims to do) then these other things easily take care of the 1% remaining stink. So I'm definitely leaning towards getting me one of those!
A few considerations I uncovered today regarding carbon scrubbing:
1) High humidity negatively affects the carbon's ability to filter the air (I don't know
why, but there it is)
2) Dust can easily clog the pores of the charcoal/carbon, rapidly reducing its effective life. The MountainAir uses a prefilter that needs changing every 3 months. Someone recommended using commercial ventilation hood filters as an alternative.
3) Refilling of many commercially manufactured scrubbers is possible (MountainAir sells replacement carbon), though adequate compaction is often difficult to achieve without special tools (vibrating table thingie, rubber mallet, etc), and in many cases disassembling and reassembling can be tricky.
That's about it for now...