The CDM 315 is a great lamp. I personally prefer the 4200K version for its spectrum, but it is not as efficient as the Agro.
Many of the reported yields per Watt are very true - but look at the yield per square meter and the costs of the fixtures and yearly lamp replacements. You need about 3.5 CDM 315s to replace a single 1000W HPS.
As I already remarked earlier: lower PPFD gives you a higher yield per Watt.