I really enjoyed Lunar: Silver Star Story Complete...but Lunar Legend was a disappointment, and the battles were boring as hell. (Not to mention LL has random battles, and I hate random battles)
As for how long the game takes to beat: normally 14-16 hours.
FF4 was the better of the two games.
Chrono Trigger wasn't really as great as so many people said it was. (Though I did like the soundtrack and the characters a lot.)
I've played all five BoF games, and IV is probably my favorite. It does have weak characters and a sometimes frustrating camera, but other than that it is a very good game.
I found III to get very boring after a while. It's only saving grace was the characters. As for I and II...the first was...