Just a quick further note on Apex: I've installed the group (well Apex/Rival mix) on my bike this Spring, and so far it has been great.
Caveat: I use flat bars, but the shifters are true double-tap/10spd (sort of Rival + level).
Apex crank (50/34), front/rear der., Rival cassette 12-32 and chain.
Shifting is great (fast and accurate), and I don't notice 'gaps' at all, but do use the bigger cogs at times on hills.
One note: as someone else pointed out, the crank on the Roubaix Comp Apex isn't Apex; it's from a lower series and somewhat heavier (if that matters).