I gain 500 feet on my commute in. I average about 9 mph. I'm never in a hurry, especially on 60psi 32c tires. On the way home, about 18 but again, this is just casual riding. I've been thinking about a 28c tire with higher pressures to increase my efficiency a little. I'm an old guy and enjoy just putting along.
I'd say my commuter/hybrid is about 15% less efficient uphill and about 35% less efficient than my road bike at speed or on a downhill.