I played both games, and I must say, their quality is staggering.
I can hardly say which game I like most. The quality of artwork (you must love the portraits!

), gameplay and storytelling is certainly better in Exit Fate... SCF really advanced in the course of time.
But the setting of Last Scenario really fascinates me and you are somehow ...closer to the protagonists and the story isn't told as
distantly as it is in Exit Fate. (And I like the battle system of LS a bit better, too... the "spellcards" make it extremely tactical.

)
They are not really comparable, but recently it felt for me like Quintessence would be on par with their quality...

it is a very different game, but it does an extremely good job of character development and the feelings of the protagonists without being too emo.

It has a good balance of tragical and humorous moments, too.