The CQC-7 is basically a production version of his handmade only CQC-6. Demand for the 6 was high, so Ernie did the collab with Benchmade to provide a production and cost effective piece, hence the CQC-7 in the BM970 and BM975SBT configurations. This was back in the days before Ernie had his own production knife company. He parted ways with Benchmade and started his own production company to offer his own lineup of knives.
Materials are very similar, 154CM steel, Ti liners, G-10 scales. The Wave is a big difference, as is the tip-up carry on EKI knives compared to the older Benchmade being tip-down only.
I have several of each one, and the newest production EKI CQC7 has a little thicker liner lock than the previous generations, and the BM97xxx series. Other minor differences are the screws, going from torx on the BM to philips and straight on the EKI model. I you love the Benchmade one, you'll likely be very happy with the EKI model too. Only downside, some EKI models tend to have a bit rougher opening action than the BM's did. This goes away after a couple weeks of opening/closing though. Not a big deal in my opinion.