Hi jade, your cousin has got a unique name by the way
Sony Xperia Z2 is way way better than samsung s5
Don't go by looks lady see what is inside,
It has 20.7 MP camera than 16MP of S5
It is water proof and dust proof so do underwater photography, has a bullet proof glass. it has 3GB RAM, this is the best thing you can get and is way less expensive.
Go tell pookie my friend helped me buy a better phone than him
Pick the Xperia Z2. And I'm gonna tell you why in bulleted points.
The battery life is amazing. Experiencing my friend's device for a week made me notice this. Everyday, I use the phone under LTE. I tend to browse, watch videos, takes photos and WhatsApp/Viber a lot. It still gets me through the day where at around 5PM I'm down to 30%. I use the phone a lot so my screen on time reaches to upto 6 - 7 hours.
The display is crisp and clear. Unlike the previous Zs, Sony has done a really good job in optimizing their displays and learned from their mistakes. Watching movies and TV shows and what not is a joy.
Camera, is also another standpoint for the Z2.
Performance is buttery smooth. You get 3GB of RAM (that's 1GB more than the Galaxy S5) and you can be assured that it's futureproof. Sony's interface is very simple and it just works.
The Samsung Galaxy S5 is all plastic. I'm not hating on it or anything but I just prefer buying a device which comes in metal or all glass. You are anyway paying for a premium device which isn't cheap. So your best bet is to go with the Xperia Z2.