I bought three of these and used them on a Glas 18650 mech mod. Good vapor production and flavor. The 0.2 ohm produced better vapor, but it got pretty hot. The 0.5 ohm was cooler, produced less vapor, and was milder overall. These things are easy to top fill, but taking them apart to replace the coil is a little tricky. You need to put something in the air vent to keep it from spinning, then the bottom will come off. As I said, I ordered three tanks, but one of them was a lemon. As soon as I hooked it up to my mod the whole mod got super hot to a dangerous level. Eciggity was great with customer service and gave me a new tank that worked fine. Overall, I would give it an A-.