We all said iphone is a big brand and name is enough to known all, but iphone is a popular brand only for apperance and camra feature and other side battery is a problem for iphone users. IPhone is costly as compare to the galaxy.
If we talking about galaxy phones is better than iPhone. Galaxy is providing the same feature in less amount .galaxy battery capacity is good, camera and video also good. I upgraded mine and it shows no problem at all. the use of ram is more clear than before.
I do suggest that you make a factory reset to the phone or hard reset. Probably you may have app which(viruses spam) drain your battery by using the processor and ram of the phone continuously.