I was familiar with this work from seminary days. Because of it's age, it lacks much of insights from recent archeological and textual research. However, the price was too attractive to pass up. Due to the age and very conservative approach of the work, I always use it in conjuction with more recent and more moderate commentaries.
The Keil & Delitzsch Commentary on the Old Testament is an excellent value. I have been aware of this commentary for years, but when I saw it at the excellent price which Christianbook.com has, I had to buy it! I was aware of the excellent scholarship of Keil & Delitzsch, but having my own copies of the books has far exceeded expectaions!