[fjtorres]

Like I said, a matter of philosophy.
More fundamentally, and the thrust of this thread, is that when comparing reader devices font support, the final word comes from the reader app and how it is designed to work.
Some apps submit totally to the hardwired file format while others give the power to the user. FBReader, btw, in all incarnations follows that guideline. It ignores hardwired formatting in ePub. So, no; FBReader180 is not a hack but rather a fork that adds a control panel to dynamically edit the stylesheet in use.

ePub may let you define dozens of fonts but if the reader app ignores them it makes no difference than if it defined but one and relied on the reader app to parse the tags according to an external stylesheet. To some this is a bug (especially if they are editors hellbent on forcing *their* choices upon the paying customer), to others it is a feature (Let's say the paying customer who really wants all his books formatted to the same font style and size).
In the olden days the editor/formatter was the ultimate unassailable authority on how a book was to be formatted. Those days are gone. (Unless we're talking pretend-paper pdf.)
Today the ultimate authority is the rendering app.

Which is why end-user typographical controls are proving to be a value-add for many ebook buyers. It may "peeve" editors but we the readers pay the freight and we get to have it our way. Even it means reading in comic book sans.

(Or more realistically, 28 point Georgia, like my mother.)

One last time: file format typography is secondary to the rendering app. Fact.
I'm outta here!