When it comes to smartphones, all conversations should start with the HTC One M8 ($649, £549 and AU$899 off-contract) and the iPhone 6 (starting at $199 on-contract, £539 and AU$549 off-contract).

Attempting to enter the arena of the big dogs, Asus' new Zenfone 2 (starting at $200, £120, AU$210 for 2GB RAM) is a handy device with a few neat tricks up its sleeve.

The HTC One M8, which we've voted the best smartphone in the world, boasts a Snapdragon 801 processor that functions at 2.5ghz, which makes it perfect for gaming, movies, photography and web browsing. At only 5.64 ounces (160g) and 5.76 inches tall (146.4mm), the Full HD HTC One M8 is a well-designed, Android-based device that accomplishes everything you'll need a smartphone to accomplish.

On the same end of the spectrum, the iPhone 6 and its iOS 8 operating system are a pleasure to use. Featuring a 4.7-inch (119.3mm) retina HD screen, and an A8 processor that operates at 1.8ghz, the iPhone one of the prettiest and fastest smartphones on the planet. It doesn't hurt that it only weighs 4.55 ounces (129 grams) either.
Design

The new Lollipop-based Asus phone features a hard plastic chassis that will be available in multiple colors in the US, including silver and red. It features a 5.5 inch (139.7mm) Full HD Corning Gorilla Glass 3 screen and weighs a hefty 6oz (170g). At only six inches long (152.5mm) the ZenFone 2 shouldn't weigh as much as it does, but you'll hardly notice a difference when compared to the HTC One M8. If weight is a major factor for you, the iPhone is a much lighter choice.

The silver bezel features a shiny matte finish along the back of the phone and along the bottom edge of the front. The front upper and side panels are built with shiny black plastic that is reminiscent of older iPhones. Your home, back and window buttons are tiny and unobtrusive at the bottom front of the phone.

At 0.43 inches (10.9mm) thick, the Zenfone is noticeably thicker than the iPhone 6 (0.27 inches, 6.9mm) and the HTC One M8 (0.37 inches, 9.4mm). Partly to blame for the Zenfone's size problem is its replaceable back panel, which allows users to swap out SIM cards.

The Zenfone's battery runs at 3000 mAh. Similar milliamp phones, like the Oppo Find 7A, feature six-hour battery lives. Asus refused to give an estimate for the Zenfone, but they did say that - thanks to Intel's Fast Charging Technology - it can charge from 0-60% in 40 minutes, which is in line with the fastest-charging phones in the world. Unfortunately, the battery can't be replaced.

Despite the size and weight issues, it's definitely an attractive device, especially when you factor in the multiple available color options.

Features

Remember those neat tricks I mentioned? Well, the Zenfone has a time-saving trick that most of you will love. From the phone's locked desktop, you can scribble a command (such as the letter C) onto the screen and the device will automatically open the pre-determined application. If you draw a C, you'll unlock the camera. If you draw a W you'll unlock the web browser.

You can set these commands to whatever application you'd like: so if you never use your web browser but you always use Facebook, you can set it up so that if you draw a W you'll see your Facebook feed. Unfortunately, you can only set five commands. But that's a cool start.

Another innovative feature is the phone's double-tap to shrink command. By tapping your thumb against the screen you'll be able to shrink the size of your desktop to 60% of its normal size. This is ideal for one-handed smartphone use, which can get clumsy when trying to reach the farthest corners of your screen.

Photographers will absolutely love the Zenfone's 13 megapixel camera, which is darn good for a smartphone. The iPhone features an 8mp main camera, while the HTC One M8 features a disappointing 4mp camera. Neither holds a candle to the Nokia Lumia 1020, which sports a 41-megapixel camera - the best in the business.

The Zenfone runs a 64-bit Intel Quadcore Z3580 processor that tops out at 2.3 GHz - just slower than the HTC One M8, but faster than the iPhone 6. It's a zippy phone that will accomplish most of your business and personal tasks with ease.

The Zenfone 2 packs a lot of cool features into one speedy little device. It's easy on the eyes, nice to touch, and offers time- and space-saving features that make it a joy to use. Its 13-megapixel camera will make shutterbugs happy, and its fast-charging battery won't leave you in a lurch on getaways. However, the Zenfone 2 is a bit heavier and thicker than the iPhone and it doesn't run as fast as the HTC One M8, so it will probably find itself sitting near the lower end of the upper echelon of new devices.

- Manohar