I'd pass on anything northwest and ToH myself. I like the Capital Renaissance, but this is definitely affected by my fondness of Shuangjing that few tourists are likely to share or appreciate. As such, I'm guessing Novotel Peace would win this battle if you had the luxury of lots of opinions.

That said, since your main objective is to visit Badaling, (NE) 2nd or 3rd Ring is marginally more convenient than the center.