CCDs are subject to many defects and this is why most other cameras are sold with an option of 'Class 1' or 'Class 2' chips. Sony have only one class for general production and this is equivalent to Class 1, or better. Their specification allows for up to 6 'white blemishes' (hot pixels) but no other obvious faults.
Hot pixels are caused by defects in the silicon crystal which generate large numbers of thermally produced electrons. In most pixels the main source of such electrons is at the silicon surface where there are lots of unpaired atomic bonds, but the Sony chips deal with these by sweeping them away through the 'HAD' layer in the pixel surface. However, if the electrons originate deep within the pixel, the HAD layer has no effect and they get stored in the charge well alongside the photoelectrons from the image.
As CCDs age, they often develop a few more hot pixels due to cosmic ray damage or migrating silicon crystal defects, but they are rarely a serious problem. Most users get rid of these spots by using a defective pixel map to automatically remove them during calibration, but a median filter will also work well.
'Hot' Pixels & the MX7
The 'ExView' chips (MX7) have a deeper pixel structure than the 'SuperHAD' chips (MX5/MX9) to enhance their QE, but this gives more opportunities for defects in the crystal and so the MX7 has more (and more obvious) hot pixels than the other cameras.
'Hot' Pixels & the SXV
The nature of dark current generation in the SXV is such that there is a tendency for there to be two 'populations' of pixels. One (the great majority) are at about 0.002 electrons per second, while the second population (very few) is at about 0.1 to 1 electron per second. These higher dark current pixels can be considered 'warm', but not really 'hot', as they do not saturate within many minutes of exposure time. As a rough guide, most chips have about 10 pixels at about 1 electron per second and perhaps 100 at around 0.1 electron per second.
As the dark charge builds up during an exposure, the warm pixels will tend to become more visible above the background, but this is counteracted by the increasing signal from the sky and objects being imaged, so they may remain difficult to see. The worst case is with narrow band filters, such as H-alpha, where the sky signal is weak and the warm pixels will show through. Because they are usually very isolated, they are easily removed by a statistical low-pass filter (3x3 median), sigma summing of slightly displaced multiple images, or by using a 'warm pixel map' to kill them.
Warm pixels do come (and go) with time, but I find the SXV-H9 to be particularly stable and my prototypes have hardly changed over two years (and counting) of use.