But hey, we've got plenty of time to extol the virtues of Serenity. Let's take a look at the ending.
"We'll pass through it soon enough..."
The battle is over, the ship is repaired, the dead are mourned and the crew is ready to take off.
The Operative that had been menacing them throughout the plot mentions that as important as what just happened was, the fight isn't over by a long shot. Mal takes on the pilot's chair (more on that later) and prepares to take off. Then this exchange happens...
Capt. Malcolm Reynolds: ...it ain't all buttons and charts, little albatross. You know what the first rule of flying is? Well, I suppose you do, since you already know what I'm about to say.
River Tam: I do. But I like to hear you say it.
Capt. Malcolm Reynolds: Love. You can learn all the math in the 'Verse, but you take a boat in the air that you don't love, she'll shake you off just as sure as the turning of the worlds. Love keeps her in the air when she oughta fall down, tells you she's hurtin' 'fore she keens. Makes her a home.
River Tam: Storm's getting worse.
Capt. Malcolm Reynolds: We'll pass through it soon enough.
On the one hand, it sucks that the series and this universe in general are probably dead so far as television/movies are concerned (though who knows? they did get a full movie made out of a TV series that lasted barely a dozen episodes). On the other hand, seeing the ship fly off to untold adventures, with those characters that I'd come to love fading with the credits...it just seems fitting.
Plus, Joss can't kill them this way.