This is obviously anecdotal: I keep wanting to support iFixit and I still come back to them despite their increased cost + shipping compared to Amazon because I believe in good QC from a reputable company and I believe in their mission.

Unfortunately I have been burned twice. First iPod batteries: They seems like they are sitting around forever and are of the same quality as what you'd find on Amazon (they look the same as well).

Secondly I was super excited for their magnetic mat with marker. All the youtubers were promoting it and I snatched it up despite it seeming quite pricy for what you get. The marker failed after 1-2 uses. In both the iPod battery + marker case, they were willing to ship replacements but it takes time and is a hassle and by then the enthusiasm is gone. I walked away thinking what did I pay extra for?

Also after using their toolkits for a while, I don't consider their tools top tier quality anymore, just middle of the road and does not seem worth the price (maybe during their black friday deals it is more palatable).