What taste better, an apple or an orange?
Depends on the person.

Like Cmdr Jennifer said:
@Cmdr:

The destroyer in my mind is the submarine of old with the ability to defend itself against air attack in place of the sneak shot ability.

In my mind, the submarine is the new piece on the board.  Here’s a cheap unit you can toss out for naval attacks and it helps keep your opponent honest.

The sub is a new type of unit, which acts differently than in any other A&A games.

Sure, there are some things we miss about it - but now subs can move about without getting hit by aircraft!

This is awesome!  :-D

A side note: sub stalling is not a problem any more. (A&A Pacific)

Think of subs as a different unit, with new strategies to come up with.

Think of subs as an attackers unit.    :-)

One example, after the US fleet has moved away from sz56 (West coast), subs can be mobilized in sz56 and catch up with the main fleet with out needing AC/ftr protection from Japan’s aircraft.