Dark spots iPhone 5S

Hi their,
I've been having quite a few issues with my iPhone 5S these past couple of weeks. Initially the iPhone 5S that I had purchased as quite bad back-light bleeding on the top and bottom of the screen, and was quite noticable in dark environments, as anyone was able to pick up on the back-light bleeding. I took the phone back to the Apple store, and they replaced the phone after quite a hefty argument due to them being reluctant in replacing the product... The new replacement that I have now, has an acceptable level of backlight bleeding that I am very happy with, however I have dark spots surrounding the screen, most noticable on the top of the screen... As iOS7 is based around white background, it makes matters worse and it's most noticable on a white background. My older iPhone 4 has absoulutely no problems with backlight bleeding, LED or LCD issues through the whole period I used it, up from launch day to a few months ago. I've taken some photos of my iPhone 5S' dark spots as well as my iPad 4 as a comparison;

iPhone 5S:

https://drive.google.com/folderview?id=0B1JNDxg5xsrJRzFDZWpHMVBwdkE&usp=sharing

iPad 4:

https://drive.google.com/folderview?id=0B1JNDxg5xsrJMWV5RXhWSGQyUUk&usp=sharing

I have also noticed that when viewing my iPhone from a tilt their is a shadowy glow on the top of the screen, of which my iPad, nor iPhone, nor my previous iPhone 5S had... I understand that IPS screen, are not supposed to have this black, shadowy, perspective. Its just quite annoying as I can pin-point the LED's on the top of the screen quite easily... I may be very picky, but I've signed up to a two year contact with this phone..

I would love any opinions that anyone may have in regards to this, thank you!

Do you think I should put up with it? Take it to the Apple Store for a replacement? I understand this is all because Apple uses LCD as their screen, but surely they shouldn't be of such poor quality - deeming the fact that my iPad was replaced three times, phone already replaced once?