What is evil about switching PS?

[wrenchone]

Unfortunately, electronics buyers now consider switching power supplies to be commodity items that you can buy like jellybeans from the lowest bidder. Even less fortunate, a lot of purported switching power supply manufacturers don't know how to design them well, especially the second and third tier producers that get the business for DVD players, etc. Most of them don't know how to lay out switching power supplies. This is really too bad, as even the best design can be totally compromised by a crappy layout. As for a mediocre or crappy design - well. you get the picture. Innovations in SMPS ICs have made them easier to design, but they still remain switching power supplies - if you don't know how to lay them out, they won't work well, if at all.