The racket that "wins" is the racket that works best for you, as I'm sure you've heard before.
I have a couple of years experience with the HPS 6.1 and 3 days experience with the nCode 61 95. My nCode experience has been on clay only. I have no experience with the Diablo. My concern with the Diablo would be that it would too light for me. (I generally like to play with stock rackets, so I tend toward heavier stock rackets.)
In a nutshell, the nCode 95 plays very similarly to the HPS. The nCode is a little more dampened with a little more power and a little more solid feel. The nCode is maybe slightly more maneuverable.
On groundstrokes, I've had to concentrate slightly more to keep form and technique with the nCode to ensure balls don't sail. On the other hand, I don't think I need to exert as much effort while hitting out with the nCode to create good spin and pace, which is a real benefit on clay.
Topspin backhands are noticeably easier for me to hit with the nCode. Serves, overheads and service returns seem to be a bit easier to hit with the nCode. Stab shots are more solid with the nCode. The limited volleys I've hit seem slightly more solid with the nCode.
So, so far I've been very happy with the nCode and it appears to be a stick that suits me better than the HPS. However, I've only hit with it for 3 days against competition that has not really pressed me. I've very curious to see how I do with the nCode against stiffer competition, particularly against one playing buddy (a teaching pro) who hits with heavy pace and spin and usually with consistency. With this player, I generally first test his consistency and if its there, I then need to force action and not let him get too comfortable. I'm curious to see if I'll be able to control the nCode under these circumstances. My guess is that the nCode will help me against this player, but we'll see !
Anyway, I hope this helps you.