well, i own both. and use both regularly.
Arc10 is much more power, and if thats how you want to play, a mix of control and power, go for it.
NS7k is more defensive oriented, and if you like to drop more, itll fit you better. but you can smash with it. its not thaat bad in the power department.
if you are in san jose...well, i guess fremont UBC is a bit far, but otherwise i wouldnt mine letting you try.