The only things BHB7 and B5E share are the fact that they're (1) black (2) shaped, and (3) both produce a ton of spin and 'grab' on the ball. Apart from that they're quite different strings.
At the same tension:-
- B5E is low powered, much stiffer and doesn't have much feel. It fact, it feels pretty dead. It's also hard on the arm if you play alot of tennis. Control is very good - primarily due to the fact its low powered; its practically impossible to hit the ball out of the court with this string. You can topspin everything without the fear of the ball flying. If you can live with its characteristics, it a good string for taming a power racquet. This string forces you to play a more patient game based on constructing points, creating openings, and finding angles rather than hitting through the court. Alot of people seem to prefer it as a hybrid, but its not something I've tried.
- BHB7 is at the other end of the spectrum. It's not stiff at all, in fact, its very springy, its fairly powerful but not overly so. Produces a very heavy ball if you've got half decent technique. Performance longevity is excellent - it holds it performance much better than any other poly I've tried. The string allows you to hit through the court much more than B5E as well as allowing you to construct points. 17 runs very thin - probably close to 1.20-1.22mm, 16 is probably around 1.24-1.26. I'd be going for the 16 if I had a 100/16x19 with any sort of 'oomph' to the racquet.
Neither string is particularly good for touch play. B5E 17 is a bit too dead and BHB7 17 is a bit too springy (the 16 is less springy).
