Although this two-part article is arguably somewhat biased, it does a pretty good job of describing the tradeoffs that are involved between the leading types of power transformers:
http://bryston.com/newsletters/84_files/vol8is4.html
http://bryston.com/newsletters/85_files/vol8is5.html
Regards,
-- Al
http://bryston.com/newsletters/84_files/vol8is4.html
http://bryston.com/newsletters/85_files/vol8is5.html
Regards,
-- Al