Switch to TBC

Currently enjoying SOM, but I'm interested in TBC. Never played it. I know its going to be a bit rough leaving behind the +40% quest exp rate, but I was wondering how the leveling experience is in TBC. With an increased level cap of 70, are the earlier levels any faster than standard classic?.. or is reaching 60 the same time investment as reaching 60 in classic, and then you have 10 more to go?