I made it through most of the game without help, but Asellus's quest with the semilinear event triggers was too much.
Amelia, Red, and T260G have the best quests, as they are more linear and easy to follow. My personal favorite, however, was Lute's, as his only goal is to get strong enough to beat his final boss, who he can challenge minutes into the game. Consequently, he was the only character that I was able to experiment with enough to actually create an original fighter (Swordsman with high holy magic skill to get the Light Sword spell which made one of the most powerful swords in the game, but was only learned by my magic users in other cases).
Red/Alkaiser and T260G are also some of the most fun characters to use because of their very cool abilities. They also have decent stories.
Bleu is cool late game, but his quest is repetetive if played late in.
Riki is the worst character in the game, due to the fact that most of his forms are very weak. A Plot twist at the end made it almost impossible to win for me.
Asellus has a terrible quest with a promising story that has some very unsatisfactory endings possible.
The developer's room is cool when you beat all seven quests, but it is not worth the sheer repetition, as you will repeat about half of the optional quests every time.
That said, the fluctuating level of challenge actually provided some very satisfying battles when I conquered an enemy that should have been too strong for me and found weapons that were far above my general party strength. I do have some very good memories of the game, including the awesome 5 character combo hits against Red's final boss.