Ok, since there's been a few requests and no fulfillment, I'll tell you what it's like for the Marines. Mind you, I speak for an East Coast experience, so anyone on the West coast, know that results may vary.
First things first, go watch Ears Open, Eyeballs Click. Great documentary, but it only depicts about half of what goes on. Then find the three-part documentary that's always on the Discovery Channel and the Military Channel "Making Marines." Much less accurate as the other documentary, but still has a lot of realistic experiences. Then search Drill Instructor Ambush on YouTube and watch all the results you can find. Again, realize that's only the half of it. I think you see where I'm going with this.
For the first few weeks, "Phase One" as it's known, life is hellish and absolutely horrible. You miss home. You have nicotine and alcohol withdrawals. You get treated like **** by your Drill Instructors and your peers. You hate life and your decision to do this crazy *** task of joining the Marines. This is the breaking down stage, and nothing could ever be worse than this.
By the start of Phase Two, you begin to see that teamwork is the only way off the island. Sure, you're still getting humiliated and destroyed by the Drill Instructors, but at least you finally realize that you're in this together and less tension between your peers exists.
Towards the beginning of the third and final phrase comes the Crucible, a 3-day real-time simulation of war ending in a ten mile hike and your final test. Once that's over, you gain a lot more respect from the DIs and life gets a lot better, mainly because you have earned it. In the past, the Crucible took place right before graduation and was symbolic of earning your right to the title of Marine. To some, it is still seen that way, and the accolades that follow, while still rough in those last two weeks, are greatly earned and appreciated.
For those unlucky ones who happen to get dropped from training for any reason, there's Special Training Company. Whether it's because you're broken, have a life-threatening illness like pneumonia, you get put into rehabilitation platoons, where life is much more relaxed but only because most of the people there hate life and have no clue if they'll leave the island with the title of Marine or not, let alone when they'll leave. I spent two weeks there, and mind you it was very much depressing. STC is also where you get sent for Physical Conditioning Platoon, where you can't meet PT requirements or are too fat to continue. Completely opposite as in it's much more hellish, but still has that depressing air of "Am I ever gonna get out of here?"
Don't take my word for any of this though. This was a year and a half ago, and for the past five years or so there have been some serious overhauls. The main complaint? It's getting too easy. USMC Boot camp has always been known for it's difficulty, but thanks to Mothers Of America everything's gotten softer for the most part. No more cursing, no more beatdowns for those who deserve it. Apparently now, they can't even use the trademark "knifehand" that Drill Instructors are known so well for. It's producing much more weak-minded Marines, and the only thing that kept me from falling under that category was having a father who was in for decades and reminded me of what the "Old Corps" is all about.
Nevertheless, it's still as memorable as it was in decades past, and it's one of those things you look back at and relish in every memory of it. You may hate it as you go through, but definitely not once you're gone.