OK, impressions of the Laurent's ripped demo:
First the bad news - the way he made the ISO, it will not work with the HDLoader. I cannot test if it will work burned on a DVD and played on a modded console.
Good news - with some minimal work, his ISO can be made to work with HDLoader and it works perfectly, loads quickly and all is good.
What you need to do, if you want to play this using the HDL is is to extract all the files from his ISO, and put them into a new, properly made ISO. You have to use CDGenPS2.exe to make your ISO, and to make it properly, you HAVE TO drag the SYSTEM.CNF file first to the list of files in the CDGenPS2 window, then drag the executable file SCUS_973.39, then the other two folders with content, being 'MGS' and 'sce_dd' (you can freely exclude the empty folders, and the two desktop.db files he put in the ISO (he probably built the ISO on the Macintosh so those two are system files))
Now copy this ISO to your HDD, and voila, the OPM front end boots, you go to 'Playground', select MGS3 and it werkzt! I have not tried yet building an ISO that boots directly into MGS3 (that requires editing the SYSTEM.CNF), but I will when I get home from work.
In any case, with five minutes of work, his ISO can be rebuild and played successfully.
Now for the demo, I have played it for the total of five minutes before I had to leave (damn you WORK!) so here are some super brief impressions:
First the bad news: The demo, and I can say this with utmost certainty, to put all the doubt aside - runs at
30FPS. After I started moving Snake around, and he made couple of steps, I was a bit like "oh, hell no". But it is 30FPS. In both 3rd and 1st person view (as there was some discusion about it during the E3)
Now the good news: Despite that, the game is just scorchingly gorgeous. Without a shred of doubt it's the best looking PS2 game, and I think hardly anyone would disagree if I say that it's one of the best looking games - period. It really does look like those screens we've been seing all this time, abeit in lower resolution, of course, but the look and feel those screens were giving away is definitely there, there are no jarring problems that would ruin the picture, and in motion it actually looks even better. Also, if you, for example, thought that 30FPS in Silent Hill 2/3/4 does not look distracting, you will think the same here. Due to the CPU controlled nature of camera, you don't get to see too many quick camera motions unless you go to first person view (and even there you can't move the view too quickly), and since nothing is moving to fast, 30FPS is not really a problem, except, of course for those of us who just wished it had that extra 'MGS' smoothness. I can tell you, though, once you see how much more complex this looks compared to MGS2, you will understand why they couldn't make it run at 60FPS.
The demo starts off with a HALO jump cutscene, much like the E3 demo, you land, have a conversation with the Major, and then are instructed to go look for the backpack. After that, it becomes instantly obvious how much more environemnt interaction there is than in previosu MGS games, or most games for that matter. When you run through the tall grass, it sways back and forth, when you slide down the slope, he slides nicely, you can press yourself against the trees, you can climb some of them, when you run around it just seems like there is actual ground you're running at, not some flat surface, like in most games. It's hard to describe, but little things like that, the way the character animation blends with the environment, and the way character interacts with it on some micro-level, and all the appropriate sounds, just makes you 'feel' the environment like few games ever did (Ico comes to mind).
I ended my demo session after obtaining the backpack, as I was already late to work, but you get to see/hear another radio sequence at that point (it's like 'codec' sequence). Much like in MGS2, you can skip through these by pressing the triangle key. Now, I'm at work, and no work is being done, as the damn demo is the only thing I can think about

)
Buy the damned magazin, own a piece of history. Even a great pir8 such as myself will fold and put down the ten coins for this one, yarrrr.
I WILL buy the mag regardless (for the other demos), but I'm not going to wait damned two weeks if I can get the MGS3 demo now.