Ok, long story short, when i vape standing up or sitting down on a chair i can inhale my 12mg juice and exhale just fine.
Now, when im laying down, sometimes its unbearable to exhale. Super scratchy which makes me cough about 5/10 puffs. Weird i know. lol.
Now, for some juice i have noticed that they have a harsh/scratchy exhale but it fine for inhale. Usually those are higher nic levels than my liking (my friend likes to vape 24mg which is UNBEARABLE to me. i don't even enjoy it). Remember to stay hydrated as well. Ive encountered scratchy throat when ive been vaping for a while with no water. Other times it is the juice and not the nic content or dehydration.
As for madvapes juices, never tried them. I like to stick with MEL, GLV, and Ahlusion.