With all the different grades of materials now being used to fabricate frames, it's almost impossible to say one material is better than the next.

For instance: Aluminum being used by one frame maker can (and most likely will) ride completely different than aluminum from another brand. The wall thickness, butting, joints, angles and swagging will all change the ride quality and the material itself can range from high end Deda U2 to low end 6000 series aluminum and everywhere in between.

Same goes for Ti frames. 6/3 frames will ride a lot different than 3/2 frames.

Carbon frames: Well it gets really interesting here because most carbon frames are built using aluminum lugs (except monocouque frames). Aluminum and carbon don't tend to get along to well, so if the frame is not built properly and these materials react poorly, HELLO disaster (see also: Trek Y bikes) Also the way a carbon frame is constructed (bladder v. 2 piece) will yield considerable difference.

Steel is no different. Depending on grade of steel, your bike could be a light and lively climber or a bogged down pig in the mud.

In fact, you can make an aluminum bike ride with more spring than a Ti, if you chose to do so and make a carbon frame more stiff than an aluminum frame.

So you see, it's really a matter of material quality, design and construction process that will dictate ride quality, not the type of metal.

Ride a bunch and see for yourself.