I'm guessing you didn't watch either film in an iMax cinema with the benefit of a massive screen and an even more massive soundstage. Both films are designed to provide an epic and visceral experience with more immediate grab than a tube of no-more-nails extra strong. I'm also willing to bet that your friend who loved the second film so much had seen at least that one at a cinema. I took my in-laws to see it at an iMax, and even they, who are normally contemptuous of anything later than Lawrence of Arabia, thought it was good. It is occasionally like sitting next to a jet-fighter, with overwhelming sound and vibratiion.
That aside, I enjoyed both films and I've also watched them since. I did a review after watching the first one
here which I don't think is unreasonable, except that I've done the rewatching and probably like them both more.
Other points. I liked the books when I read them, but I was only 18 and going through a period of devouring around 3 or 4 books a week. I kind of remember them, but I have no real idea whether TV shows and films have affected my memory. In any case, a book is a book and a film is a film. Some people get angry when there are plot changes, which is understandable if the aim of a film is to somehow act-out the book, but the best films, I think, stand on their own whether they are "true" to the text or not. They aren't the book. If only a book will do, what's the point of the film? That said, sometimes there are things being set out in a book, which are worth sticking to in a film if they are "the point" of the story. If you don't then the director risks losing the logic or ethics of the story. Could be fine if their is something else to say instead, but if there isn't...
And yes, getting to like a film after first being bored by it. Sounds like my experience with Stalker. I was immediately caught up in the atmosphere and visuals of Stalker, but it has a relentless quality like some extended bit of modern jazz, and it lost me around a third of the way through. I came back to it a year or so later when somebody gave me an awful copy on a CD. Somehow watching it again, I kind of got it, in a way I hadn't before. I love it now and it must be one of my favourite films.