Red Saber is awesome, Red Saber best Saber. And for a first playthrough, she's the best choice, as she's the strongest of the three, and not knowing the enemy patterns at first won't hurt you so much.
Anyway, about the game itself, I liked it. Plot's pretty good for a tournament setting, although there were some inconsistencies, and the antagonist's motivations wasn't that great and is actually a simplification of a point that could have been explored way more in-depth. But it's fun. Gameplay's not really that good, gets pretty repetitive after a while. But Red Saber makes it worth it.