Chris Welch, The Verge:
Next up is the QX1, which is really meant for people who’ve already invested in Sony’s Alpha / NEX line of interchangeable-lens cameras. There’s no lens in the box; instead, the QX1 is basically a $400 adapter with the brains of Sony’s A5000. It’s got a 20.1-megapixel APS-C sensor, Sony’s BIONZ X image processing, and even a built-in flash.
The Sony Alpha a5000 with a 16-50mm lens is priced at US$448 on Amazon. Not only is it more expensive, the QX1 is bulky, slower, and more cumbersome to use than the a5000. The only advantage the QX1 has over the a5000 is the viewfinder (your smartphone) can be separated from the camera.