uPVC (Sometimes written PVC-U) is a frame made out of un-plasticized polyvinyl chloride. It is the most widely used material for window and door frames nowadays, for very good reason.
Aluminium is very versatile and all frames are thermally broken so condensation cannot travel through the metal. We always supply "A" rated glazing as standard.
Although timber is more expensive than other materials, some would say that the advantages they offer are priceless. Timber alternatives offer the uPVC advantaged with a Timber look and feel.