Harry Potter and the Philosopher's Stone (aka Harry Potter and the Sorcerer's Stone), is a very accurate adaptation of the eponym book by J.K. Rowling. And that's the problem.
The first book of the Harry Potter series is a very good and fun read. But one of his flaws is that it goes from from small adventure to another without a real captivating story. Even though it isn't such of a complain in the book, it becomes really visible in the film. This movie adaptation is exactly that, an adaptation. Chapter by chapter, scene by scene, we live the same events as in the book. But we don't really have a strong connection with Harry Potter, which is the main character. In the book, we feel his pain and loneliness in the first chapters, then his bond with Ron and Hermione. We live his struggle to prove himself. In the film, the character is surely there, but we don't really feel anything at all. Except at the end of the movie, when things finally start to take shape and the stakes are higher.
It may be as well that the reason is in the casting of Harry Potter himself. Surely, Daniel Radcliffe is a very cute boy and he is the perfect face for Harry Potter. But we can clearly see that Daniel Radcliffe is not a great actor. He seems to say his lines as if learned by heart, without truly believing in or living those. On the contrary, Emma Watson is simply perfect in her performance of Hermione Ginger.
Rupert Grint also plays a marvelous Ron Weasley, even though his performance lacks a bit.
Coming back to the major flaw of the movie, it seems that the director is screaming "Action!", then the children are citing their lines, and then he says "Cut!". But the scenes should roll and live like a theater play!
For those reasons, I give the movie a 3 out of 5. A good average or a low good. But definitely not great.