blakerwry said:
An external PSU is cheaper, user replaceable, and lowers engineering costs.
I don't think this is true. You may lower design costs for your appliance, but the external power supplies will cost more than an internal. Apart from anything else, regulatory requirements are tougher to meet on external bricks.
Heat dissipation can actually be harder to manage with a brick - you may notice that they frequently run quite hot. Good for your applicance, but not for the brick.
I'd even disagree with the user replaceable aspect. In PCs, for example, power supplies are mostly standardized units available anywhere. In contrast, even appliance models from the same manufacturer may have distinct brick variants. And what happens if a user connects the wrong unit?
Good grief, you can't even get standardized connectors, let alone standard polarity (or AC/DC) and voltages.