There's no doubt that the Galaxy S6 and the S6 Edge are the most advanced handsets that Samsung has ever made. With the release of the Galaxy S6 Active, Samsung is offering a bigger battery option that has earned mixed reactions from early adopters of the company's latest flagship devices.

The Galaxy S6 and S6 Edge both offer respectable battery life with their respective 2,550 mAh and 2,600 mAh batteries. However, their predecessor, the Galaxy S5, is equipped with a bigger 2,800 mAh battery. Probing further, it's interesting to note how the new Galaxy S6 Active's 3,500 mAh battery somehow places the company's recently-released flagships in the middle of sibling rivalry.

Here's a closer look at Samsung's duo-turned-trio of Galaxy S6 devices.

Samsung Galaxy S6 Active: The most significant feature of the S6 Active is its 3,500 mAh battery, which is absolutely bigger than the batteries found in the S6 and S6 Edge by almost 1,000 mAh. Designed with a rugged exterior, the newly-released handset is said to cater to users who enjoy being outdoors. Other notable features include the handset's quad-HD Super AMOLED display of 5.1 inches, an Exynos 7420 octa-core processor of 64 bits, 16 MP rear camera with 5132 by 2988 pixel resolution, 5 MP front camera, internal storage of 32 GB, Android 5.0.1 Lollipop, Touchwiz and nano SIM.

Samsung Galaxy S6 Edge: As mentioned earlier, the S6 Edge boasts a 2,600 mAh battery that delivers talk time of up to 18 hours and music play of up to 50 hours. It bears the same camera specs found in the S6 Active, including the same resolution. With its uniquely-designed curved edge screen, it seemed like the perfect handset to finally achieve the best selfies and groupies using its 120-degree wide-angle selfie camera.

Samsung Galaxy S6: The S6's 2,550 mAh battery means that it is around 1.02 percent smaller than the S6 Edge and around 1.4 percent smaller than the S6 Active. Samsung explains that the difference in the battery sizes correlates to the SIM tray location. By placing it at the top of the S6 Edge, Samsung was able to include a slightly bigger battery in the curved-edged model, although the difference is minimal and may even be unnoticeable.

All three handsets are capable of Samsung's built-in wireless charging system.

The Galaxy S6 Active will go on sale beginning June 12. Currently, the handset is exclusively available at AT&T. At $0 down, users can get the S6 Active on monthly prices that range from $23.17 to $34.75.

At this point, it's still too early to tell how the new S6 Active will fare against its "not-so-older" siblings when it comes to battery performance. Users of the original duo flagships are already unimpressed with the devices' battery life. However, the company tries to compensate it by equipping the phones with a fast charging system. The S6, for example, can charge up to around 35 percent in a span of 10 to 15 minutes. It can reach 100 percent in around one hour and 20 minutes, which is faster compared with its rivals. In addition to this feature, Samsung has also designed the handsets with two power-saving modes called "Standard Power Saving Mode" and the "Ultra Power Saving Mode."

While there's no mention of the two power-saving modes in the S6 Active, the device truly lives up to its rugged impression with its IP68 rating on dust- and water-resistance. It also meets the Mil-STD-810G standard that allows it to resist vibration, shock, humidity, temperature and pressure.

In other words, users who are keen on their device's battery life should also take into consideration the design that comes with a much bigger battery. A bigger battery means a more robust, rugged and bigger build. Slimmer designs would have to be equipped with a similarly "slimmer" battery.