I trained both and arena abused Sophia. If you want an easy way, use Ray and don't bother with Sophia. However, if your like me and are patient enough to train Sophia (Arena), then you'll find that she turns out better in the end. She pretty much had the same stats as Ray, if not better, except in skill. That's the only thing Ray beats her on. I used just about every magic user in FE6 on my first play through, so I know who's good. And Sophia outclasses Niime.