My Father has been using Samsung Galaxy E7 for two years and he seems very much satisfied. He would say that the device doesnt get freezed like others samsung mobiles phones.
Its been two years and still he didnt have any malfuction on his E7. The cameras are working well and the screen sensitivity is responsive as new. The smartphone is powered by 1.2 GHz quad core processor which is fast.
It has been a quiet an interesting experience for him. My dad had two years of ownership and expecting his Samsung Galaxy to perform consistently. Its a good smart phone.