Gosh, I've owned a lot of 66" one-piece R/D bows. I'll be honest. I am not impressed with the Black Widow; It is a good bow, not a great bow.
I am very impressed with and still own the following bows that you might consider:
A&H ACS (one-piece)
Leon Stewart Slammer (I prefer this bow to his R/D, and I own both)
Fox Triple Crown
Big River 21st Century (copy)
21st Century Edge (The workmanship on the bow isn't the very best, but they are shooters.)
These are the best out there in my opinion. Good luck!