The Samsung Galaxy Core II is quite nice. the only problem is, ones the batterie is damged, and even when you charge a brand new one, you got the heating problem. I had it for one year now, and the battery was damged after a few months, so I had to change it, but it heats tell the phone is some how blocked, the screen starts to show colors and stuff, so I remove the battery, let the phone cool down a littel and place it back, and it works for a few minutes but the problem seems to appear back.
I made a factory rest, tried the mico-software updates, even changed again the battery but nothing seems to work. I followed the heating source and it comes from the back of the micro sim’s area. I think it’s a CPU hardware problem. in conclusion, if you buy one, it will be a great phone for a couple of months, then, buy a real smartphone.