This is the most highly popular material for windows and doors today, this benefits from little or no external  maintenance and this is an excellent, highly insulate material, this is the lowset cost option out of the three materials. Internally beaded windows (where the double glazing glass is held from the inside) is considered more secure and burgular resistant. A much more environmentally friendly choice as you will be keeping your home warmer by insulating it rather than using energy from central heating.