I'm sorry, I thought everyone was gonna vote for BoA.
I'll wait though.
If I'm being honest here, I'm just not going to vote. I feel I haven't heard enough from either of them to make a decision. WILD is in my top 5 songs of all time and Come is a masterpiece, but so far I've enjoyed a larger amount of songs from BoA.
I don't know about everyone else in this thread, but it's pretty easy for me to pick out my favorite's in J-pop since my dad and I lived in Japan for 13 years. I was essentially raised on Namie and BoA from the time they debuted.