At earlier levels of gear you might find the resources spent in Expertise for the hard cap hurt your energy regen to much. I've tried both and personal found I'd rather have the extra resources/chi that Haste provides and just deal with the "bumps" when the come occasional from the misses.
Even as I gear up I'm thinking I'd rather put extra rating into Crit for more EB uptime than expertise. As others have said ultimately it depends on which approach makes downing bosses easier so your free to give both a shot.