It depends on what you need, and what you're actually able to clear. Ocean of Heaven(Neptune stage is best) offers good loot, a lot of gold, and decent exp. If you can clear the Starlight Sanctuary stages reliably, I'd say those are better. I'm not comfortable farming the last 3 stages of SS, but I can regularly farm the second Ceres stage. I discovered that the gold and exp per stamina ratings on the wikis are incorrect. I actually get 30-40K gold and over 7000 exp per run, and the drops are higher leveled, so they provide more exp as feeders or more gold when sold. So, the gold is only a little less, but the exp/stam is much better than Ocean of Heaven. The rare drops are a toss up between whether you prefer Dub-mythlits and Gold Kings or Mystic Masks and Metal Kings. I'd be farming SS Zeus stage or Legendary Earth: Celestial Black Dragon all day if I could work out a team that made it safe and reliable.
Wow. And I thought I had great luck maxing out my Verche with only 10 MLKs.