I always compare it to those Pegasus class hydrofoils the U.S. Navy used to have; now just add a twin-barrel eight inch gun to that hydrofoil and add forty reloads for its missile launchers and you've got tiny warship that moves really fast and carries as much firepower as a heavy cruiser.
That's it exactly.
It's not that she's a more powerful ship than, say, a heavy cruiser, its that she's as well armed as a larger ship while being faster and more maneuverable, and it's that edge of speed and maneuverability that allows her to have a slight edge on comparably-armed vessels. I would tend to think that three coordinated Keldon
-class ships might have been able to defeat her handily. Even a gnat gets swatted eventually.
She was apparently outmatched by three Jem'Hadar bugs in 'The Search.' Perhaps the bugs are equivalently armed?
I wonder who win win in a fight of Enterprise
-E versus Defiant
, or E versus D? All three would theoretically be similarly armed (excluding the D's lack of quantorps) but I would think the difference would again lay in speed and agility.