I got it yesterday, and I think both the artbook and the guide are really great. The print and paper quality are fantastic. I'm a big sucker for tasteful use of paper texture and quality gloss and matte lamination, and they certainly did it nicely here. Both books just feel very rich and nicely textured to touch.
As for the content, the comic book excerpt is there, at the end of the guide book, and the poster is also there, it's a really nice picture from the game, btw (the one with the Snake with the croc hat in the mangrove location).
The art book has tons or character art, mostly from MGS1, then MGS3, and the least from MGS2 - which is somewhat unfortunate, because from what is presented there, you can tell how Shinkawa's techniques progressed as he was working on the series. Guide book is thicker, content is very nicely laid out, but I didn't want to flip through it too much, as I'm still not nearly done with the game.
We don't get stuff like this in US very often, and importing books from Japan usually costs a lot more, so in short, I think the whole package is well worth the money.