Dunno about Utd, don't see Chelsea though. He'd benchwarm at Chelsea. He's a clever lad; he's playing every week at Everton and with Euro 2016 next year, he'll want to get into the full squad.
His temperament and mindset is similar to Baines, very grounded. Baines didn't agitate for a move and I doubt Stones would either. It all comes down to big money. Everyone knows English talent has a premium price (look at LFC/Sterling) and it's whether or not Utd would pay the £30m+ at least it would take to sign Stones.
He also has 3 years left on his contract, which is fairly significant in terms of finances involved.
Can't see it myself.