I'm on my 3rd type B cylinder atty since September 9. They seem to die with an open coil after about 3 to 4 weeks. I'm hoping that my first two were flukes. I have the cone and the cylinder attys and both yield good taste and vapor. Certain juices do make me cough with the cylinder, especially the 100% PG juices. Backwoods Brew juices are smooth through the cylinder atty and have outstanding flavor. The mix is 70%pg/30%vg and that is probably the difference.
On both the type A and the type B attys, I have found the polyfill to be the least troublesome cart filler, provided that you create a looser fitting filler than the one that comes in the cart. Some of the factory carts are packed too tight and run dry due to marginal feeding. If your atty barrel gets hot, it may be running on the dry side and that can contribute to early atty failure not to mention a vapor that makes you cough. These things like the right mix in the bowl to run efficiently.