Mid 20s Instance farming

So, tomorrow night I will have cleared and done all quests in WC, SFK and BFD - And I expect I'll be halfways through 24 or so on the 5 man shammy team.

Now, I assume next instance would be Razor K? And I'm guessing I can start to run it effectively around 28 at the earliest - So, the question then becomes - Any opinions or views which of WC, RFK or BFD to farm? They seem to be about the same level range to me, so they should be similar xp - From pure layout I would say SFK is to prefer, as it's fairly small and easy to navigate.

Any other thoughts?

SFk is best, gives most exp in my opinion and is quite easy (besides arugal)

Took my group into SFK today at 25 just to see if it was any faster than questing.

I was getting the same XP from level 18-20 elites that I did from level 25-27 normal mobs while taking more mana to kill.

But I assume I was doing it wrong. I'll always prefer questing since grinding reminds me of Lineage II (that was the only way to level).