I have the Alcoscan AL7000 and have used it many times over the years. I originally purchased it to test guests leaving my son's wedding in 2011 to make sure everyone would get home safely, and have since used it every time I have gone wine tasting or have taken guests wine tasting. Even if they aren't driving, it helps them recognize how quickly their blood alcohol can rise. Many other breathalyzers have to be sent in yearly to be recalibrated, so just re-ordering a simply installed sensor module every year has been wonderful.
I am currently in Reno, NV and they have lowered the limit to .005 so it's even more important to test even if you just have a glass of wine when you're out to dinner.
This is a wonderful unit!