My personal opinion - I don't think I would want to use a product with 20% alcohol as the preservative. I want to use products I know contain proven preservatives, and my skin couldn't handle that much alcohol in a leave in product. Alcohol is incredibly astringent, so adding it to a moisturizing lotion would leave me a lot less moisturized than I expect! Alcohol is also a known irritant - if you have sensitive skin, a lotion containing alcohol could sting!
If you're selling lotions, please note that in a lot of places, you need a permit to sell a product containing alcohol. And please get it tested. Get your lotion tested at 1 month, 2 months, 6 months, and one year before you even consider selling it.
So many products are labelled "alcohol-free", I wonder why moving to using alcohol as a preservative is considered more "natural"?
If you're using alcohol as an effective preservative - one you've tested - let us know about it by posting a comment here! What percentage are you using, and in what kind of product?