Really, there was no choice. Williams returned and Giacchino got to play s stormtrooper in the new film. So everyone wins!
I've seen a lot of negative responses to Williams new score for The Force Awakens. I'm a bit surprised by this. This score is really great in a lot of ways. But it is certainly not written in the style of the 1970s and 1980s Star Wars scores. John Williams has not written in that style in a long long time. HIs style is more complex, more detailed and in a lot of ways more dynamic than his older work. But this means that the simple clear themes he used to write are few and far between.
A perfect example of his new style of theme is this lovely one he created for the new character Rey. It actually has three different elements to it, and Williams uses each element in different ways throughout the score. Sometimes he uses a single element, like the rhythm that opens this track. Other times he uses two portions, or all three of them. This theme is also highly malleable, as he can make it sound mysterious, frightened, horrified and noble. This is a testament to Williams skill. But, there is no obvious "hook" in this theme. During the film you aren't really given a clear obvious single statement of the full theme. But he uses it in various guises the entire time.
For me, this is a clear winner of a theme, and the more you listen to the score, the more you hear Williams genius at work. I'm really looking forward to hearing the next couple Star Wars scores to hear how this theme changes as the character and her story evolve.
So here is Rey's Theme from The Force Awakens, by John Williams