Today, it's the LG G4 versus the Samsung Galaxy S6 versus the Apple iPhone 6 versus the HTC One M9. Who will win in this four-way slugfest?

The Apple iPhone 6 Specs

Released in September last year, the Apple iPhone 6 is a 4.7-inch phone with a light and slim profile at 129g and 138.1 x 67 x 6.9mm. It supports multi touch, and supports Apple Pay and Touch ID. It has an 8MP main camera and a 1.2MP front camera as well. It has a non-removable Li-Po 1810 mAh battery for power.

The iPhone 6 has the iOS 8 which is upgradable to iOS 8.3. Under the hood, it is powered by the Apple A8 chipset containing a dual-core 1.4 GHz Cyclone CPU and a PowerVR GX6450 with 1GB RAM.

Its non-expandable internal storage has three variations : 16GB, 64GB, and 128GB.

The HTC One M9 Specs

Out since last March, the HTC One M9, running on Android 5.0, has a 144.6 x 69.7 x 9.6mm dimension and 157g weight. A Li-Po 2840 mAh battery powers this 5-inch phone which also sports a 20.7MP main clicker and 4MP secondary cam.

Inside, the HTC One M9 has a Qualcomm MSM8994 Snapdragon 810 chipset that has two CPUs, a Quad-core 1.5 GHz Cortex-A53 and a Quad-core 2 GHz Cortex-A57, and an Adreno 430 GPU. It has 3GB RAM and its internal 32GB storage is expandable up to 128GB via microSD.

The LG G4 Specs

Launched in April, the LG G4 is powered by an Octa-Core Qualcomm Snapdragon 810 processor, with a 3GB RAM running the core and apps of its Android 5.0 (Lollipop) OS. 

This 5.3-inch LTE-ready smartphone has an internal memory of 32GB which is expandable up to 128GB via microSD. It comes with a 16MP main camera and a 8MP secondary camera. A removable 3,500 mAH provides power to this smartphone unit. Yes, we said removable. It uses a nano-sim, and comes with a stylus as well.

The LG G4 is 148.9 x 76.5 x 9.9mm in dimension, and has a curved back design with a large camera lens cover.

The Samsung Galaxy S6

Also launched in April, the Samsung Galaxy S6 is a 5.1-inch phone with a profile of 143.4 x 70.5 x 6.8mm and a weight of 138g. It has a 16MP main camera and 5MP front camera, and has a Li-Ion 2550 mAh battery.

The Samsung Galaxy S6 runs on Android OS, v5.0.2 with 3GB RAM. Its Exynos 7420 is powered by two CPUs as well, a Quad-core 1.5 GHz Cortex-A53 and a Quad-core 2.1 GHz Cortex-A57, and a Mali-T760MP8 GPU. Its non-expandable internal storage has 3 variations too: 32GB, 64GB, and 128GB.

The Review: From Camera to Overall Performance

"If we had to pick one winner out of all of these, it'd be the Samsung Galaxy S6, with the LG G4 coming in a close second. And to be honest, the iPhone 6 isn't far behind that," wrote Mobile Nations managing editor Derek Kessler in his review of the phones' cameras.

There are some who think the LG G4 has a better camera, though, with purported DSLR quality captures. The camera has an optical image stabilization and laser auto focus, and the manual mode allows users to control image attributes such as white balance, ISO, manual focus and shutter speed. The LG G4 camera is notable since the shutter speed feature is not found in other smartphones in its category, with available ranges from 1/6000th of a second up to 30 seconds.

The fact that HTC One M9 received a camera improvement update not long ago could have had an impact on why it wasn't included in the review. Nonetheless, the update is still a step towards the right direction for the Taiwanese phone maker and users have since noted the significant improvement.

It's easier to make a call on the camera aspect. Of course, we have to look at everything the units have to offer.

While we do not claim to be the experts here, one thing seems to be a concensus though: the HTC One M9 places last among the four. The company's sales figures apparently speaks for itself.

Overall, its really a slim margin between the LG G4, Samsung Galaxy S6, and the Apple iPhone 6. What spells the difference is probably the support provided by their respective companies and the preferrence of the user.