Although he has produced a brilliant hundred against Sri Lanka of recent, it doesn't tell us a lot about him.
Only his consistent performance (or not) in the series can have the final say.
Not to discourage or downsize the wonderful effort to rescue India beside his captain, one must understand that he hasn't solved his age-old problems in batting.
He still gets out LBW while playing across the line and still gets out (or comprehensively beaten) by fishing for the ball outside the off stump.
However, he has evolved from his early days. He is arguably one of the best players of spin in this side next only to Tendulkar. Dhoni, Sewhag and the others can negotiate spin well just like any Indian batsman can. But Gambhir's technique is solid- he uses his feet immaculately, while he cuts and pulls with ridiculous ease. His inside out shots are as good any you shall see in the international arena.
The way he picked Murali's doosra in the last game shows the kind of player he becomes when he is full of confidence- which he was after scoring an enterprising 70 (till then). His six off Malinga shows that he has the power to clear the ropes, which was sadly devoid of some Indian batsmen who have graced the stage.
It can be safely said that he is the best No.3 in this side. I'm absolutely sure that it is time to say goodbye for sure to Dravid- his slow accumulation has been a constant bane to the side, and with Gambhir now finding his destiny, India can forget those bad days.