I bought my Diadem Nova FS 100 Plus in 2021. For years, I've strung all my rackets with poly in the mains and X One Biophase in the crosses, and I continued with this racket. I decided to try Dark Matter, and I love the string. The only reason I didn't give it 5 stars is that it frayed within two weeks of being strung.

Great easy to play with string

Great, arm friendly string for my junior player. Another fantastic product from Diadem. I'm not surprised, I've come to expect it.

First, I'll start by saying that I haven't been a big fan of black strings. Just a color thing, so no 5 stars. However, these just might make me change my mind.
Other string reviewers have said that black strings give a bit more control than their natural counterparts, so not having a natural color to compare it with makes that comparison impossible in this case.
Not being a poly fan I traditionally play and prefer a firm feeling multi, Technifibre Triax, X1 Biphase or Babolat Xalt always in 17g.
Ok, now the string performs very well strung a Nova 100, full bed at 58lbs mains and 55lbs crosses. (I prefer a firm feeling string bed so I my up the tension to 60Lbs). On initial feel, it gave a good firm feeling for a "comfort" multi, not mushy or springy. (think Volkl Power fiber, too soft / springy).
Firm enough to feel connected and still able to feel pocketing to generate spin. Varying the launch on shots was good, you didn't always have that high launch angle that soft multi's often have. So far tension maintenance is good, haven't had enough time to give a good assessment on that. Rally balls land deep in the court, generating spin on sharp angle groundies good while still able to flatten out when needed. volleys feel great and you can get a nice low ball on slices. great feeling on one handed backhand, able to get good spin and still able to flatten it out when needed. Easy power on serves.
I may have found my new string of choice, great playability and a good price.
(now just waiting for a natural or white color).