When beginning to (self) study a new book I find myself spending quite a bit of time searching around my library sampling commentaries in my library as well as searching for reviews to try and get a sense of any given commentary. When searching for guides to commentaries I first bumped into bestcommentaries.com which has been helpful, particularly as a listing of what's out there, but rather uneven in its treatment due to its aggregate method. I have found one good resource but is unfortunately short on each.
There are quite a number of 'recommended commentary' pages that are aimed more towards pastors or those engaging in devotional study, these are not what I'm looking for. I have also seen a few forum discussions on broad sweeping judgments on commentary series while acknowledging that all the series vary in quality by book.
I recognize that different commentaries have their strengths and readers will always differ on preferences. I am looking for a description of what the strongest commentaries are on a given book and what their strengths are specifically. Said differently, I'm looking for someone's take on what commentaries they found most helpful and why (why being the salient feature.) I'm interested in critical rather than homiletical commentaries.