I read this the first week it came out and was suprised by how much it rehashed GOF and the Core J2EE patterns books; however I have referred back to it on "Unit of Work" and a couple other concepts that it helped to differentiate. TO it's credit it consolidated information from several bodies of knowledge in patterns, and it provided c# examples in many cases, thereby being the first high profile work that really exposed MS developers to a world of patterns, that was arguably previously unknown. Besides being somewhat lacking in originality, the other problems were the fact it actually catalogued anti-patterns as patterns (e.g. transaction script is basically unmaintainable web pages), and it addressed enterprise system architecture without paying any mind to integration concerns (see Hohpe for an excellent treatment of this subject); I'm not sure the two really are separable when we start talking about business services. The best thing about this book is that it emphasizes the criticality of rich domain models in complex systems, which IMHO is a core design principle which is currently being eroded by a current of irrational and marketing-drunk SOA furor ... which reminds me, Domain Driven Design is not to be missed, it's simply an inspired work which helps to make Fowler's domain model achievable for almost anyone.