OA was only [relatively] recently approved here in the states. Some folks are giving it a bad rap...I think mostly because they don't understand how to use it correctly and effectively. My MAQS have always come with an instruction sheet, and instructions and FAQS are available on NOD Global's website, yet a bunch of people can't seem to use *that* correctly either and then cry about it not working or killing their bees.
Then the same folks go down to the hardware store and buy a bag of wood bleach, which has no instructions at all, order a vaporizer on-line, and then complain that *that* doesn't work either, because they only gave one treatment, at the wrong time.
I know that cost-wise, OA may be less expensive than MAQS, but proper use of OAV requires multiple applications at defined intervals over a particular timespan. That is not a suitable routine for me, I have too many other things going on. MAQS is pretty much one shot, 'set and forget'.
On a related note, my wife went down to Mass to visit friends and relatives this weekend. Yesterday she stopped in to Crystal Bee Supply in Peabody, and it happened to be package pick-up day, cars were parked up and down the road for a considerable distance and a long line snaked around the building while the packages were being unloaded from a trailer.
My wife grew up just a couple of miles away from the location and is friendly with the owners. She went in and was chatting with them, and mentioned that she was surprised to see so many people and so many packages. The owner said "It was a very bad Winter and all of their bees died." My wife was surprised, she was down there multiple times during the Winter, it's 200 miles south of where we live and it is nowhere near as bad as what we get here. I lived and worked down there for nearly 30 years after coming back to NE from out west, and before that spent most of my Winters there when I was a kid, so I have the experience of nearly 50 Winters there. The 200 miles makes a huge difference, something to do with how the Arctic air-mass sits and moves, it rarely gets down as low as zero there, while here we can pretty much count on stretches of 20 to 30 below. Up here, our snow can start in October, and it isn't unusual for us to still be seeing snowstorms until the end of April. Down there, a white Xmas is a crapshoot, frost danger is pretty much over by March and you can start putting seeds in the ground.
So, given our experience with Winters here, she was quite surprised and she started chatting with some of the customers, in particular, what they did as far as treating for mites. she got a lot of strange looks, seems that a lot of them don't 'believe' in 'treatments'. One guy had some drone frames in his hands and told her that that was all he did. She tried to tell him that culling drones was only going to buy him a little time, not solve the problem, but he clearly didn't want to hear it and she gave up. Similar results from the other people she talked to. Although she didn't talk to enough people to really get a statistically valid sample, it was fairly evident that the mindset around there was 'all natural' and 'no treat'. She left, shaking her head at the shear stupidity of it all, people buying packages every year to replace their bees that died because they won't do effective mite treatments. Given our experience here, with almost no Winter losses over the last three years despite our much more severe Winters, she knows that a 'bad Winter' isn't the issue.
I had been telling her fairly recently about my frustration in talking to people on other bee boards, who repeatedly lose their bees because they don't/won't do anything worthwhile for mite control, but she didn't think it was that bad until she talked to some of them herself (she doesn't get into chat boards like this). She called me right after she left the shop, utterly amazed and now understanding just how stupid some people can be.