Massive decision for Stones, could make or break his career.
Going to City and playing under a manager with similar playing philosophy's as Martinez could ruin him, as could playing for a ruthless manager such as Mourinho. The mistakes he has made for us have gone under the radar for many Pundits but if he'd made those mistakes at UTD, City or Barcelona then they would have been magnified.
The best move would be to stay and hope Koeman can bring the best out of him. Playing under a manager that was also a defender could be the best decision. He needs a year out of the spotlight.
Saying that if a bid of £45m came in for him id sell ha ha.