After researching Genesis commentaries online, I picked one for a preparatory overview, Goldingay's Genesis for Everyone, and then selected the top four more academic ones, starting with the least-rated of the four and working up to the top. The least-rated was Waltke's, better rated was Mathews', then Hamilton's, with the highest rating going to Wenham's superb commentary.
I felt that each was valuable in its own way. Waltke's was a great follow-up to Goldingay, being concise, but without omissions (includes the modern theological tie-ins), yet was contained in one volume. Mathews', like Waltke's and Goldingay's, was easy to read. I felt like there was a jump in quality, however, when going to Hamilton's commentary. It's difficult to say which is the better commentary between Hamilton and Wenham. Wenham's, I think is weightier with far more, up-to-date, well-researched information, but harder to "shlog" through (especially given the Word series' format). Overall, the one to have is Wenham's.