The iPhone 5 features an 8MP camera with a f/2.5 aperture and a 1/3.2-inch sensor giving each pixel a size of 1.4 micrometers. The HTC One has a 4MP camera with a f/2.0 aperture and a 1/3.2-inch sensor giving each pixel a size of 2 micrometers.
As you can see in the samples below the iPhone 5 generally outperforms the HTC One camera in daylight situations; however the HTC One does better in low light conditions due its larger pixels and wider aperture.
We've posted some of the comparison images below. The iPhone 5 is on the left and the HTC One is on the right. A full gallery of comparison photos can be found at the link below.
[iPhone 5 (left), HTC One (right)]