Hello! And sorry if this counts as an old post resurrection...
But I'm having similar issues and feel very let down by this tank, I bought it 3 weeks ago and I've been through 8 coils.... I prime them properly, and work them in slowly before vaping about 2 tanks a day at about 40W.
I can't get them up to 60W or anywherenear 70, I have to vape at about 45W or I get a horrible burnt taste every couple of hits or so. I've seen in reviews that 70W is the ideal vape wattage for the most commonly used coils, I've tried the 0.25, 0.5 and 0.15 temp coils but they all last no longer than 3 days max. This current coil I put in this morning and is now giving me grief already at 46W! Less than 24 hours, it seems to be getting worse somehow.
I'm hoping to build a decent RBA coil for the crown to save me from throwing it completely. I'm looking for another tank at the moment anyway, and can't understand the rave reviews or the fact that the shop I bought it from claimed they can vape it above 100W...