These windows are taking me a long time to 'decypher'. I kind of talked about that above. They all have slightly different features, slightly different warranties, slightly different performance.
What I haven't done yet is to check price. That will probably be a big deciding factor - because everthing else looks largely equal.
I am looking at Marvin and Loewen. The Marvins are more expensive than the Loewens. And as far as I can tell ... they both seem to have the same quality and performance and warranty. Or I guess I should say that their features are so close that I can't detect a material difference.
So ... I'll price a similar window in both manufactures and see how far off they are from each other.