I'd say these are as good a mirror effect as you can get for 5 quid. While the frame looks cheap it is actually quite sturdy, if not perfectly set. The hinges are pretty solid too. Aviators have thin frames anyway, so when you are wearing them no one looks twice. They look pretty good and protect your eyes. If you want high fashion get your cash out. If you want cheap, looks good, and will last for a holiday or two, then look no further.
So in summary....don't expect RayBans for this price. Nothing wrong with these for looking good on a summer holiday. Also, as a bonus, there's no need to stress if they break in your suitcase, you can afford another pair!