IF you go Ataru Striker, taking Seer will be an Out of Career spec, so it'l be 10XP higher than if you started with Makashi Duelist. However, Ataru is a seriously badass spec, particularly since it does include multiples of both Parry and Reflect, whereas Makashi Duelist lacks any Reflect talents, but has more Parry talents. a good complement to Ataru is Soresu. It's probably the best defensive form there is, whereas Ataru is the best offensive form. Somoen who is a master of both would be seriously badass.
One other thing you should consider when making your choice is your career skills as well, not just the talents. What base Career overall, do you want your character to be. Starting as a Ataru Striker, you're a Seeker, which includes both Piloting skills as well as Survival, Vigilance and Knowledge (Xenology) on top of the Ataru Strikers skills. Makashi Duelist is a Mystic, which has Coercion, Charm, Knowledge (Lore), Knowledge (Outer Rim), Perception, and Vigilance as it's career skills.