[mathil]

@Michal Jancik: As others told you and as has been discussed at length in the thread, white bezels can give the impression that the screen is darker when compared to a model with black bezels, it's an optical illusion (I'm referring to the devices with the lighting turned off). The zoomed letter on the Libra also looks sharper to me compared to the Clara, though to be fair the picture quality is quite poor, so it can be difficult to tell.
If you don't like the lighting however, considering that there can be variation between devices, you might be better off returning it and getting a new one. As long as the lighting is even, differences in color between different models can definitely be expected. But you also mentioned that the screen stopped responding and you had to reboot 5 times: even better reason to return it IMO. You might have a faulty device.