I think I would, unless you plan on sitting at the bar, the waiting is horrendous at Planet Hollywood!! Yes, you can make ADRs at PH, it's even available on the Disney Dining site online.
Considering you get $15 for free when you stay on property, I'd say they will take any business they can get. A lot of competition has popped up at DTD in recent years, and PH is likely not doing as well as they used to.
We've always had great food at PH. The only thing I don't like is it's so stinking loud in there. I LOVE the bruschetta. In fact, I was thinking of going in just to get that. It is the best I've ever had