I have lots of investment properties which have contained hundreds of Pella and Andersen vinyl and aluminum clad windows and doors.
In my experience they are both complete junk. Both brands have leaked badly and both have suffered catastrophic failures with frequent rotting of the lower or bottom rail . The trouble is that neither company ever figured out how to keep the water out.
Making matters worse, it is my belief that the management of both companies lied about these window and door failures, in most cases, claiming that the products were not defective, when we all knew better. Their favorite cover story is faulty installation.
In the case of Andersen sliders, they are notorious leakers, especially in areas with higher winds. I had lots of sliders where the vinyl jamb was so flimsy that it split from frequent opening and closing, and created many hidden cracks behind the weather stripping. All that created soggy carpets and rotten wood floors.
In one house, Andersen sent out their smartest tech people, and were unable to find the leaks. As they were preparing to leave, I offered to show them their hidden leaks. They claimed that in the history of the company they had never heard of split jambs causing leaks. I do not believe them.
In Pella’s case, their windows and doors leaked so badly that in many cases the window or door rotted, and had to be replaced.
So knowing what I know, I would buy any brand except Andersen or Pella