I'm frequently hired to diagnose water intrusion problems at patio doors, and the most important factor is the quality of installation, not the quality of the door. A relatively "low quality" door properly installed is far more likely perform adequately in terms of preventing water intrusion (which is by far the most frequent serious problems with these doors) than the best quality door you can buy if it's incorrectly installed.
The exact installation technique required depends on the wall material, and the toughest jobs to do properly are retrofits into walls with multiple layers of cladding, for example vinyl siding over wood, especially if the outer layer of siding has not been installed properly (for example, the required water resistant barrier material has been omitted). Stucco is another material where an inexperienced or careless installer can create problems.
The door manufacture will provide installation instructions, but these will typically address installations in new construction, and while they may cover some recommended flashing details they typically will not cover the specific techniques required at the junctions of the wall cladding with the door - that's specific to the cladding, and often to the details of a specific installation.
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