Xiaomi’s new Mi Note Pro makes a formidable challenger to the iPhone 6 and Samsung Galaxy S6.

Like the Mi Note and Mi 4, the Mi Note Pro Xiaomi’s flavour of Android known as MUIU which, according to the company, powers 100 million phones around the world.

Xiaomi has launched the Mi Note in China, Taiwan, and Singapore but the Mi Note Pro is exclusive to China.

At RMB 2,999 ($483), it's a little more expensive than the Mi Note, which costs 569 SGD ($413) in Singapore. However, it’s still well under the price of Samsung's Galaxy S6, while its specs keep it ahead of many other Chinese rivals. Its release also comes as Chinese consumers spend up on a better mobile experience.

Xiaomi hasn't cut corners on the Mi Note Pro, which has the current generation flagship Qualcomm Snapdragon 810 processor, LTE Cat 9 radio supporting up to 450Mbps downloads, 64GB of storage, 4GB of RAM, and a 2K display. Xiaomi says the phone will get about 10 hours HD video playback on the 3000 mAh battery.

Everyone’s heard of Xiaomi, but a lesser known up-and-comer is Vivo, a Chinese smartphone brand focusing on India, Thailand, and Malaysia.

One of its newest devices, the X5Pro, bears a strong resemblance to the iPhone 6 but with a slightly larger 5.2-inch full HD display.

Despite a high-end finish, its specs are decidedly mid-range.The X5Pro runs Vivo’s Android 5.0-based Funtouch OS and comes with a 1.5GHz Qualcomm Snapdragon 615 processor, 2GB of RAM and 16GB of storage with a 2450 mAh battery.  It's got a 13 megapixel main camera and an eight-megapixel snapper on the front.

For around $450, the X5Pro faces stiff competition from similarly priced but more powerful smartphones from Xiaomi and ZTE’s new Axon Pro.

Nonetheless, Vivo's fortunes are rising fast in China. According to analyst firm CounterPoint, its second quarter shipments grew 250 percent year on year, making it the fifth biggest vendor in China.

Oppo's R7 Plus is the larger sibling to its recent R7, which sells for €349 ($382) in Europe.

The six-inch display R7 Plus isn’t available in Europe yet but pricing could be around the $480 mark.

The R7 Plus has a massive 4100 mAh battery that Oppo says will charge rapidly thanks to its Vooc charging system.

It's also running on a Qualcomm Snapdragon octacore 1.5GHz processor, with 3GB RAM, 32GB istorage, with 13 megapixel and five-megapixel cameras.

The R7 Plus ships with Android 5.1-based ColorOS v 2.1.

OnePlus ramped up development of its own OxygenOS ahead of its split with Cyanogen, whose OS it had used for its first generation device, the OnePlus One.

The first device to ship with OnePlus' homemade OxygenOS will be the new OnePlus 2.

It's likely to be one of the best pieces of hardware in 2015, but comes with the drawback that you’ll need an invite to purchase one.

Eventually the invite system will disappear and anyone will be able to purchase a OnePlus 2 but that may take several months.

The 5.5 inch display OnePlus 2 comes with all the frills of a high-end device but at half the price.

Its specs include Qualcomm Snapdragon 810 processor, 3,300 mAh battery, 4GB RAM, and USB Type C connector.

Thanks to the invite system and taking slim margins on each device, OnePlus can offer these specs at a lower the 16GB model with 3GB RAM for $329, while the 4GB RAM 64GB model costs $389.

After a INR 1000 price cut last week, Cyanogen OS fans in India can buy the Yureka Plus - launched last month - for just INR 8,999 ($141).

The Yureka Plus is the second handset from Micromax's Yu line to run Cyanogen OS. The device is powered by Cyanogen OS 12, based on Android 5.0 Lollipop.

For that price, the device's standout features are its 5.5-inch full HD display, coupled with a 13-megapixel main camera and five-megapixel front camera.

Topping it off, the Yureka Plus features Qualcom’s Snapdragon 615 processor, along with 2GB RAM and 16GB storage.

Amazon's Fire phone, which runs its FireOS Android fork, never caught on, despite some novel features like its 3D interface, Firefly scanner shopping assistant, and Mayday helpdesk.

The Fire cost Amazon dearly when it failed to take off due to its launch price of $649 for the 32GB model, but the clearance price of $169 makes it a bargain.

The Fire phone isn’t available on UK carrier O2 anymore, but the 32GB unlocked edition in the US is still available on Amazon.

The Fire features a 4.7 inch HD display (1280 x 720 pixel resolution), powered by a 2.2GHz Snapdragon 800 processor with 2GB RAM, and comes with a 13-megapixel camera as well as unlimited cloud storage for photos.

If spies, snoops, and hackers are your biggest fear, the Silent Circle’s BlackPhone 2 might be for you.

The BlackPhone 2 has privacy at its core and runs on PrivateOS, a security-focused variant of Android that’s been stripped  of numerous Google services like the Play app store. Silent Circle has its own app store, and users can add third-party stores to the device.

Central to the BlackPhone is the Silent Suite of apps for encrypted calls, messaging, contacts and calling plans to non-BlackPhone devices. Another useful feature is its virtualised 'spaces' concept, which allows users to create isolated personal hubs for different groups of apps.

The BlackPhone 2 will be available for $629 at launch, however its release has been delayed from the original July timeframe to September.

Compared to the first BlackPhone, its successor will have a larger 5.5 full HD display, 3GB RAM, 32 GB storage, as well as a 13 megapixel main camera and five-megapixel front camera. Apps are powered by a 1.7GHz Snapdragon 615 processor.