A properly set front suspension really only effects efficiency for out of the saddle efforts. Even then the difference is greatly over-stated. The trick is most hybrids and light trail bikes have coil forks which have only minimal pre-load adjustment. If you're too heavy for the spring, it will be very inefficient and bouncy. If you're too light, they don't really do much, and they're effectively locked out.

The main drawback is that they're 2-3 lbs heavier than a standard fork. Personally, my next commuter bike will be a 29er with a decent suspension fork so I can take "shortcuts" on the way home.