I actually had the same thoughts you did until I watched some highlights a while back. Barber was obviously a more physical runner, but he had a good burst when he needed it. Barber ran a 4.49 40 at his pro day. Maroney only ran a 4.51 40, which was surprising. I think both were faster than Smith/Brooks, as they are a lot more like David Cobb. Vision and power, but not as much speed.
That absolutely shocks me. My memory is of Maroney leaving everyone in the dust, and Barber, well, not.