AllThingsOnePlace on YouTube [1] has been doing a good job of reviewing performance characteristics of many different chargers, although he usually doesn't do teardowns.
I watched one of his reviews recently[1], and while it's true that he reviews performance characteristics, it's unclear whether it's something I should care about. For instance, he talks about how that particular charger has a low power factor. Sure, having a high power factor[2] is nice in theory, but is that something I should care about? Judging from the wikipedia article it's more of an issue for the grid itself, and I'm not personally billed for it. I care far more about how much noise/ripple is being outputted by the charge, or whether it's going to damage my electronics, but that's doesn't seem to be evaluated.