This will depend on where the kid feels he will get more game time and where he feels he will shine especially with it being a World Cup year.
With Madrid he will be in a country he knows well, a league he as performed well in and with one of the biggest in the country with massive exposure.
But will he get regular game time compared to CR, Otzil, Di Maria.
With City he will be working (alledgedly) with a manager who he knows and who as got him to perform at such a high level, he will also be playing for a high profile team with a national player who will go to the WC.
But he doesn't know the league and this may affect his confidence.
It's a toss of the coin but this is a massive decision for the lad, hopefully he chooses us.