Three and a half stars and a big thumbs up.

Nope, it’s not Ebert and Co. weighing in on “Harry Potter and the Sorcerer’s Stone,” but the real experts – kids who know and love the book and who managed to get a sneak peek at the movie.

The bottom line: The new Warner Bros. film rocks – but J.K. Rowling’s book is even better.

Nevertheless, the kids say, there are benefits to seeing it on the big screen. The Quidditch scenes were a hit – especially among the boys – and there was a collective gasp when the slobbering, green Mountain Troll lurched into the girls’ bathroom in pursuit of Hermione.

Everyone, it seems, is wild about Harry – and the boy who plays him, 12-year-old Daniel Radcliffe, whose dark bangs conceal the jagged lightning bolt that’s marked him for greatness.

The kids loved Hermione, too, especially when she raised her hand frantically in class, eager to show she had the answers. And at least a few young jaws dropped at the sight of Voldemort’s 11th-hour appearance.

The Potter scholars had no trouble figuring out what the movie left out – that pesty ghost Peeves, for one – but as one fifth-grader observed, “If they put in everything, the film would have been six hours long!”

As it was, it clocked in at 2½ – but most kids said it felt like half an hour. (One father said it felt like four.)

Asked how many stars – out of four – she’d give it, 10-year-old Kathleen Wickman hesitated.

“Can’t it be 5?” she asked. “It’s a 5!”

Here are some early reviews from The Post’s Popcorn Panel:

Tanya Bekker, 13

“I thought [the film] would be more Snow White-ish. I was surprised it was so suspenseful. I think you’d like the movie more if you didn’t know the book .

“Harry had a real close relationship with his owl, Hedwig, but we didn’t see that at all. And Ron was different. He looked like how I thought he would, but he was a little too brave for the character .

“I think the book was a little better because you could use your imagination. I still don’t get Quidditch.”

William Bekker, 10

“It was exciting to see what the characters actually looked like, but some characters were different. Take [Draco] Malfoy. I remember Rowling said he was very quiet. But in this he seemed very open, very rude.

“If you hadn’t read the book, the film wouldn’t have been as scary. That scene in the woods, knowing it was Voldemort drinking the unicorn’s blood . well, you know how powerful he is. It gets you scared.”

“This is worth owning on DVD.”

Kathleen Wickman, 10

“The movie left out some parts – they didn’t show the part about the potion bottles in Snapes’ classroom. Also in the book, Hagrid had given Harry a flute, and Harry used it to put the three-headed dog to sleep.

“I thought the Quidditch game was the most exciting and gross part of the movie – because Harry almost swallowed the snitch. I really want to see it again, and recommended it to my friends Charlotte and Victoria.”

Doug Murray, 6

“I’d give it a million stars! I don’t have a favorite part. It was all great.

“It was a little scary – when the Mountain Troll came, and when Fluffy, the three-headed dog, tried to get them when they were stuck behind a locked door. And Voldemort’s head .”

Does he want to see it again?

“I saw the movie again. In my dream.”

Sam Locklin, 10

“The movie was more violent than the book. I mean, Harry had blood on his face. But Draco Malfoy was wrong. The book described him as pale and quiet. [In the film] he had blond hair and looked like he was trying out for Male Model of the Year. And [Malfoy’s cohorts] Crabbe and Goyle had nothing to do. In the book, one of them gets turned into a mouse at least.

“It was a little too faithful to the book. I’ll give it 3½ stars.”

Ashleigh Rand, 9

“It was so cool, especially when Harry was picking out his wand and things exploded .

“I liked it because of the adventure, the excitement, the costumes . It was sad when Harry looked in the mirror and saw his mom and dad. But he had his friends, and that’s what mattered.

“I want to see it again!”