Of the three flagship phones already out in the market by tech giants Apple, BlackBerry, and China-based OnePlus, the OnePlus One was the first to be released. It came out in April last year, while both the iPhone 6 and the Blackberry Passport became available last September. 

In terms of the form factor, BlackBerry undoubtedly went out of the norm. Choosing to provide an almost square phone, its dimensions are that of a small booklet, hence the Passport name. It also chose to have a square, 4.5-inch screen with a 1440 x 1440 resolution. The form also comes with a physical keyboard, meant to endear the Passport to those who'd like the classic style. 

Apple and OnePlus chose a more convenient smartphone form. The OnePlus One and the iPhone 6 just differ on their dimensions and display. The One is much bigger than the iPhone 6, with a 5.5-inch display that renders 1080 x 1920 pixels. It also stands out as the clear winner in terms of pixel density, coming in at 401 ppi as opposed to Apple's newest phone at 4.7 inches displaying 326 ppi. However, the Passport takes the cake at providing crisp, clear display at 453 ppi.

All three devices have IPS multi-touch screens with 16 million colors, and the displays are provided with adequate Corning Gorilla Glass 3 protection or in the case of Apple, its patented, scratch-resistant Oleophobic coating. 

Most users also look into how much juice a smartphone packs, since it spells how much use they can get in a day. In this, the Passport is the clear winner, with a replaceable, 3450 mAh battery that allows up to 18 hours of talk time or 432 hours in standby mode. Next in line is the One that has a capacity of 3100 mAh, while the iPhone 6 comes last with just 1810 mAh that can have 250 hours of standby time.