These days, very few smartphone launches excite people enough to queue up for hours in the street. Apple's iPhones are pretty much the exception to the rule.

Yet on a warm, sticky day in central London, more than 200 people snaked around the streets outside the SwiftKey offices near London Bridge just to get a glimpse at the OnePlus 2, a smartphone few have even heard of.

Key Features 5.5in display (1920 x 1080)

Snapdragon 810/ 4GB RAM

9.85mm/175g

USB-C port

OxygenOS (based on Android 5.1)

13MP/5MP cameras

Dual SIM

Fingerprint sensor

Price: £239

Release date: 11 August (with invite)

The long queue – and the one million-plus people who have registered interest in the OnePlus 2 online – is testament to the hype the company generated on the back of the surprising success of the OnePlus One, which launched 15 months ago and sold 1.5 million units.

OnePlus 2 is selling its second smartphone (as it did its first) as a "flagship killer", and not only the flagship models from Apple and Samsung out now but the ones coming in 2016 too.

In the long run, this is not the greatest marketing gimmick and the company should simply sell its new phone on its merits and its incredibly low price –because the OnePlus 2 is simply superb.

OnePlus 2: Design

Bulky and heavy were my initial thoughts when I saw the specs announced for the OnePlus 2. At 9.5mm and 175g, is it heavier and thicker than the iPhone 6 Plus and Galaxy S6. But holding it, the first thing that came to mind was how solid it felt.

OnePlus has added a touch of premium-build quality with a metal frame around the edge, but the rear cover remains plastic – though there are alternative covers you can get with various finishes such as wood and sandstone, which is a bit like a fine sandpaper.

The phone has a large 5.5in screen but it is significantly shorter than the cumbersome iPhone 6 Plus as well as being narrower, which makes it much easier to use one-handed, though it is still a pretty big phone.

OnePlus 2: Screen

Speaking of the screen, the 1920 x 1080 pixel resolution has been held up by some critics as a sign that this is not a true competitor to the flagship models from Apple and Samsung. However, from my time with the phone, I found the screen to be perfectly adequate. I known that may sound like damning with faint praise, but it is not – I found the screen sharp and at 600 nits, it is brighter than pretty much anything else on the market.

At £239, there are going to be compromises and I am not sure many people would really notice the difference between a 2K screen and this one.

OnePlus 2: Fingerprint sensor and USB-C

The OnePlus 2 has a number of selling points, with one being the fingerprint reader that it claimed before launch was faster than the iPhone. I was sceptical but having tested it out, I am seriously impressed.

Setup was simple and it never once failed to work in any orientation I tried. Even better, you do not even need to turn on the screen to get it to work as you do with the iPhone, and you do not need to swipe like you do with some other sensors.

Other unique features include the USB-C connector for charging and data transfer, which means no longer having to figure out which way you need to hold the connector when plugging it in. Obviously the iPhone's lightning connector already has this functionality but it is impressive to see OnePlus embrace it so early compared to its Android rivals.

OnePlus 2: Performance and camera

In the brief testing I did with the phone, I found it to be fluid and responsive. There was no lag in switching between apps or launching apps. The phone is powered by a Qualcomm Snapdragon 810 chip, which received a lot of negative press for overheating issues.

At the London launch, OnePlus' Eric Zarshenas who heads up its European operation said the company had been working day and night to make sure the chipset was working perfectly and won't suffer from any overheating issues.

That included tweaking the OxygenOS software to avoid running two adjoining cores on the chip at the same time to avoid overheating and including a copper element to help dissipate heat. Only time will tell if the company has been successful.

The camera on the phone has a sensor with the same megapixel count (13) as the original but OnePlus has replaced the Sony sensor with an OmniVision sensor which features 35% larger pixels which should make low light performance much better. The camera also comes with optical image stabilisation (OIS), 4K video recording (30fps), fast-forward and slow-motion capture as well as a laser-focusing system.

In my tests, I found the camera to be fast and responsive and handled the harsh lighting in the demo room well. Obviously we will need to test the camera more but, considering it has the same sensor as the 2014 model (which I found to perform well) with added OIS and laser focus, I am optimistic for the results.

OnePlus 2: OxygenOS

OxygenOS is the skin OnePlus puts on top of Android and for the most part, this is something I particularly dislike on Android smartphones. However, version 2.0 of OxygenOS actually adds functionality to Android while keeping the look and feel of Google's software.

Customisation is key to OxygenOS and everything from easily arranging the quick settings menu to giving you granular access to each app's permissions – something that is native to iOS but not Android.

It also adds the ability to quickly launch certain functions such as the camera or flashlight by drawing on the screen, even when it is locked. It works brilliantly and is a simple solution to quickly launching certain features.

OnePlus 2: Price and release date

The phone will go on sale on 11 August in the US and across Europe. Initially, only the 64GB model will be available costing £289, with Zarshenas saying phones should be arriving with customers around two weeks later. The 16GB model costing £239 will go on sale "later in the year".

The company is once again employing an invite system for customers looking to buy the phone, meaning only those with an invite can access the store online. Invites were given out at the fan event in London and will be distributed on social media channels and the company's very active community forums.

OnePlus 2: First impressions

Having read the OnePlus 2 press release earlier in the week, I did not think the phone would be as impressive as it was. From the understated design of the OxygenOS to the fast fingerprint reader and fast performance, the OnePlus 2 is an incredibly impressive smartphone when you consider its price.

I do not think it will be for everyone the way the iPhone appeals to the masses but, as the long queues in London attest to, the phone has certainly got a lot of appeal and I expect it to be a huge success.