Here are a few relevant sections from the WMPU review of the 450W:
97% of Windows Phones may be Lumia devices but that is not to say that other manufacturers do not make interesting devices. Kazam’s Thunder 450w is a low-mid range Windows Phone produced by the eponymous UK-based OEM. The specs of the device are slightly similar to the Lumia 640 with a 720p HD screen, a Snapdragon 200 and 1 GB of RAM. Should you buy this device over any of Microsoft’s recent Lumia devices? Read on and find out.
Unlike the HTC One series and more like traditional Windows Phones, the device is made of colourful plastic. The unit I was given was lime-green, but appeared more like yellow to my eyes. It’s a cheerful design and one that I enjoyed carrying around.
Like many low-end devices aimed at the EMEA region, it comes with dual-sim support, a user-replaceable battery and a micro-sd slot with support for up to 32GB. Unsurprisingly, the back comes off to expose all these slots. The battery cover is very secure, although it doesn’t quite create the illusion of a seamless unibody handset like Lumias do, it’s quite sturdy and firm in the hand.
The only thing I’d regard as slight negatives are the buttons. The handset comes with capacitative Windows buttons as opposed to software powered ones. However, these ones do not light up in the dark, and they are quite dull and blend in with the handset, making them hard to find sometimes.
The review continues, with the expected poor ratings for screen and camera:
In terms of the former, I noted that the device produced colours which appeared muted especially when compared to the Lumia 830 and 640 which have similar configurations display wise.
While the phone does not come with Gorilla Glass or any kind of special glass, Kazam runs a screen replacement service that will replace your screen for free if your device is under warranty....
...while many phone cameras produce images that look ok on their screens and make you recoil when you see them on a computer screen, the images produced by the Kazam were equally bad no matter where I looked at them. The images weren’t terribly sharp or focused and colours were frequently off.
Michael at WMPU concluded:
Furthermore, this device has a few red-flags on it that make it unsuitable for enthusiast buyers at the moment. Firstly, it cannot run Windows 10 via the insider program as Microsoft and Kazam have not yet enabled support for it in the WPRT. The second bit of bad news? It will not be getting Windows 10 officially as well. Kazam has confirmed to us that none of its devices will be receiving Windows 10 Mobile updates, but that devices going forward will. Unless you particularly like Windows Phone 8, it would be unwise of you to pickup this iteration of the handset.
You can read the full review here.
If I sound a little bit jaded in my second hand opinions here, it's that I've seen so many cheap hardware designs coming out of Asia (despite Kazam's address), built down to a price, and with components that are horribly compromised. From screen to speaker to camera, the overall experience will just be horrible compared to caressing (say) a Lumia 640, for not much more money. As Michael concludes, buying this would be 'unwise'.