This is a nice book case for the price.  It took me about an hour to assemble by myself (would be easier with a second person.)  I like the depth of the shelves and the adjustability of their spacing.  
It is as stated, MDF, not "real" wood, but a manufactured product.  MDF is not terribly durable.  Pay attention to the manufacturer's recommendation on weight limit of 50 lbs per shelf, or they begin to sag, and do not use liquid cleaners on it.  If you follow these recommendations, you should get the 10 years out of them that the manufacturer promises. 
I have owned 5 of these bookcases in the past.  All 5 completely disintegrated when we had water intrusion into our office during a flood event.  I did like them well enough that I have just purchased this one new one.  
Barring another flood, I believe I will be happy with my purchase.