[Mekkanox]

For at least a few years now, even conventional "slushbox" automatics get better mileage than a manual transmission when in the same car.

Lower maintenance costs are usually mentioned as an advantage of manual over automatic, but slushboxes have been around for quite a while now. With routine maintenance and average use (meaning no launch control usage or burnouts), both types will last forever.

[JoeAltmaier]

You can drive a manual very efficiently. My Forester has a display showing instantaneous efficiency. I can increase mileage by a third by paying close attention to it. But that means driving very conservatively, which I'd never do without the display to remind me.

[brokenmachine]

Since I have bought a manual car, my efficiency has gone down by a ridiculous amount.

Fortunately the fun factor has gone up by the same amount so I don't care...