I have many atomizers, many authentic and many clones. Almost all of my authentics work perfectly out of the box. The only one that I had to do anything with was my brass monkey for which I replaced an o-ring out of the box because I thought the AFC ring was too loose.
As for clones, these are a few that I have used for at least a few weeks of regular use (long enough to make a good evaluation):
tugboat (tobeco) - perfect
plume veil (acerig) - orings needed to be changed for perfect fit
veritas (fasttech) - insulator melting… removed
stillare (tobeco) - no issues
454 (tobeco) - positive post spinning
cats (infinite) - positive post broken
cats (tobeco) - no issues
mephisto (vapetech) - perfect
onslaught (ivogo? - orange box)- perfect
These last two, the mephisto and onslaught are what I am
vaping right now. They are both fantastic.