Left foot!
I always signed him in FIFA, so he'll provide the balance when using 2 CDM formation. Not to mention, very easy to use and effective always.
Anyway, yeah he looks promising and his passing seems to have greater ranges and more creative than Fred/McT and far more natural than McT. On the ball he seems to be far better all-around, but Fred is more skillful. Not sure how his defensive ability is, but I'm not confident he can defend better than McT.
Could be a good long-term replacement for Matic. Add in the competition and improve our squad depth. If we're not signing any midfielder this window, then Roca is enough only if we change the system to 3 midfielders eg. 433
#8 = Pogba, Bruno, Fred, McT
#6 = Matic, Roca
Done.