There are 33 dates (with 13 potential people to date) currently available. You must complete the previous dates with that person to unlock the newer dates.

Which is the best ME3 ending?

The one critical thing to getting the best ending in ME3 is the War Assets mechanic. If you get enough war assets before your final battle against the Reapers, Commander Shepard lives, and the trilogy ends on a happier note.

Should you control or destroy the Reapers?

It is entirely up to the players interpretation to determine which ending they feel is the best conclusion for Shepards story, but the choice to control the Reapers offers the most satisfying ending to the fight for survival in the Milky Way galaxy.