These bookcases are pressed wood and knowing that you might think the quality wasn't there, but you'd be wrong.  Would a solid Cherry bookcase be better, absolutely, but for my needs (and assuming most peoples) the price just isn't justifiable.  These look fantastic, so much so that I have 5 of them, 3 in my study and two in my office.  Pushed together they look like one flowing piece.  Very sturdy once put together. Again, they are pressed wood, so take care when assembling, but once they're built, they're very solid and will have no problem holding shelves full of books.
If you catch them on sale or with a coupon, they're just that much better!