I've had a P3se for years and have accumulated both newly purchased as well as several used batteries for it and NONE have ever become swollen or failed like the batteries for my P4p.... Some of those have literally swollen after only a couple flights. The added expense and worry about P4 batteries is a joke. I'm just about ready to dump both of my P4 birds on Ebay and go solo with my P3se. I believe the P3 se has a greater overall flight time as well in comparison after using both side by side. No doubt it has something to do with all the sensors pulling power etc. Everything for the P3 se is cheaper as well. My conclusion, its no different than buying a stripped down car with fewer options, LESS THINGS TO FALL APART, BREAK AND FAIL.