I've been using Lorann peppermint oil and don't have any problems at all. It has not clogged an atty or caused any atty to die before it's time. (I consider 1 month of 100% use about normal for a Joye ego/510 atty)
I don't have any health problems from using oils such as peppermint, spearmint, orange, or cinnamon. Remember these are oils so a very little goes a long way. You can start with maybe 3 drops to 3-5 ml of juice and adjust from there.
As for not getting the flavor out of the atty. Well the atty I am using right now, previous juice I made was a "peppermint patty" type of juice I made for myself using peppermint oil. The juice after that I made was a coffee, and it does take a few vapes, maybe .5 - 1 ml of juice, but it does come out of the atty. If I'm changing flavors after an oil I try to make it one that will "blend" well with it for those 1st few vapes. It will stick around but I don't find it sticks around for long.
This is just my experience, but I have not found any of the things people are say to be true. (at least for me, but who says I'm normal to begin with)