OK this is going to be a bit long... but it will be good food for discussions.
Yes, this movie is "Hollywood". The Plot line is predictable, but it is the concepts that the director explores along the way that make it interesting an thought-provoking, assuming you pay attention and didn't just rent it for the bang-bang, or a chance to see Demi in a wet T-shirt. Ridley make some mistakes, but he does some really good things too. Let me comment on what some other people have said, and talk about what I think Ridley does well with this film.
I think Mr. Scott gets a really excellent performance from Demi. I feel this is her best film, but I haven't seen to many, because she usually gets on my nerves. However, she is believable in the role of a woman who just wants to prove to herself that she can do this. I believe her when she says she doesn't want to be a poster child for women's rights... and the Commander is right in telling her that she's gonna have to wear that hat anyway.
Viggo is great too. I don't think too many people knew who he was when this movie came out, but he was even billed above Anne Bancroft. Someone said he looks embarrassed in every scene... hogwash. He looks like a very tough character in a very difficult situation. He knows that the issue is not whether a woman can make it, many can. This isn't about women's rights... this is about how men, mainly YOUNG men, relate to women in stressful situations. If all soldiers were in their late thirties, emotionally and psychologically, then the issue would be much smaller. Most of these guys are young, dumb and full of... you know the rhyme. I was there too, once upon a time. Viggo is excellent, he reacts the way many military instructors would... trying to stop the inevitable, fighting against politicians way over his head who have never been in the crap, but think they know better. Pay attention, you can just see that he respects LT O'Neil. But he believes he has to make an example out of her. Ms. Bancroft is excellent as well, some people say over the top, they obviously haven't had to deal with high level politics before. Perhaps she is a bit rough for reality, but remember, it is a movie, making a point, and being entertaining, things have to be gritty... and Senate will always be more vicious than any military training. I find her performance fun and a joy to watch.
I don't know if Mr. Scott has any military training, but he does a better job of conveying the realities of it to the screen than most. Yes, the SERE segment goes farther than real SERE training would go... but not by much. Talk to someone who's been through it. It would not have been the same group of instructors... it's a very specialized field and the instructors have extensive psychological screening and training. However, I'll give that one to Ridley, he's trying not to complicate the plot, and he needs the scene with Master Chief Urgayle. BTW Women do go through SERE sometimes... and the instructors do use them against the men's emotions.
As for other Militray stuff, much of the language, feelings about chain of command, frustration with training constraints and political a**-covering was /On The Spot/. I speak from 6 years of experience as an Army officer (some of the stuff you see on active duty is amazing, but in the end it all balances out and the US Armed Forces are still the best in the world). Even the way Ridley has to frig with the plot to put the trainees in a an actual firefight was plausible... not possible, but plausible. Remember, it is a movie, he's got to have a real combat situation to entertain the dumber audience who just came to see the boom. But Ridley even goes far enough to give the Master Chief a chance to back out. It is a group of Navy SEAL trainees, deep into their training cycle, with a buttload of prior experience (IF you pay attention you will note that one of the trainees is a US Army Ranger, one a Marine, probably from RECON, these are guys who know the job already, and this is true to reality). You are also talking about a straight forward mission facilitating extraction of US Army Rangers from the deep inland mission. Ridley even has that right, this would be a Ranger mission, and the Spec-ops community may do a joint op where the SEALS secure the sea-side extraction point.
Quite frankly... the movie is better than most people could have done. Matter of fact, I think it was a tough challenge for Mr. Scott and don't think anyone could have done much better. One bad point I agree with is that artistically, the movie is shot entirely too dark.. that's about the worst thing I can say about it though. As for plot predictability... how often do you REALLY see an original plotline?
One last comment. I was at the Army Officer's Advance Course when this movie came out. There was a group of Officer's that were gong to see this movie, ostensibly to have a good laugh. These were Ranger-qualified Infantry guys, a Marine officer from RECON, a couple guys going to or coming from SF training... all Type A's. The next day they weren't laughing... they just said "you know what, that wasn't half bad." That don't sound like much, but it's high praise from that group.
Probably why this has such a poor rating is because it isn't Hollywood enough for the lowest-common-denominator crowd.
Enjoy the film.