Another place that is tough to tell the quality of the hardware online is those decorative tips on top of the picket called finials.  Many places charge a hefty upgrade fee per panel to add finials to the fence panel.  The worst part is these are often cheap die-cast, aluminum or plastic that ship loose and you have to glue or press them on.  The difference between the fence panel material and finial material will be come apparent over time when the dissimilar metal coatings (or materials like plastic) fade at a different rate and really start to look like a cheap add-on.  Be sure to check what those finial tips are made from and how they are attached.  Our Stronghold Iron uses solid cast-iron finial tips that are welded directly to the picket like the image below.