Hi there! I am new to the game (3 months and 3 months completely cigarette free!!!), but know for sure the K4 is my favorite. The only issue, and it's a very annoying (and costly) one, is that fluid leaks excessively through the air holes at very random times (ie, when not using, when just refilling, when just carrying it in hand, when laying down... you name it, it's happened). But, it could day 2-3 days without leaking, then suddenly BOOM, my hands or shirt or pants or inside of my bag are covered in juice.
I have gone through great measure to ensure that the platform the glass tank sits on is free from any debris (sand, dust) so that the seal is good there. I also don't over prime the cotton. And lastly, I am super careful to not get juice inside the center part when refilling.
The coils I am using are:
HEC556-CLTO-CLS-027 Replacement coils for Aspire Cleito
Resistance: 0.27ohm Clapton 40-55W (Standard with K4)
Please help with any suggestions.