Hello, we used plastic for the construction. For one window (children's room, roughly south) which we darkened during the day with the roller shutter, the roller shutter first warped and then tore after about 4 years. The reason is that heat buildup occurs behind the roller shutter. The manufacturers say that air vents must be left open - but this is impractical with electronic roller shutters and lets light through. This problem has already been discussed by others in the forum. Now I have switched to aluminum (myself, at a cost of under 60€ per sqm) and the problems are gone. In such a case, I would always choose aluminum. For windows facing north, or if the roller shutters are not supposed to be fully closed during the day, plastic would be sufficient for me, although aluminum looks better and appears more valuable. But no one sees that at night anyway....