We tend to go with Prüm, as they have pure white as a color.
Unfortunately somewhat lighter compared to others.
Regarding the color: Jeld-Wen apparently also has pure white as a color (RAL 9010), while Herholz, for example, has traffic white (RAL 9016). Whether you notice it afterwards, no idea...
About the lower weight with Prüm: I've read that somewhere else too. What's so bad about that anyway? Less sound insulation?