I'll add something to this.
The trend is the modern *professional* game is speed over spin (or at least, as much speed as you can get!)
However, I may be in the minority here, but I think for *most* people.... Spin over speed is 100% the way to go if you want to improve, win more matches and go up the rankings.
I play D09C on both sides.
I've tried Zyre - It's fast, and when you are feeling like Ma Long, you can hit some YouTube worthy shots.
But..... It's just too fast for the majority of people I think. For me, it would be a step down.
Although I'm still tempted to really try it for a season......
Zyre is both the fastest and the spinniest rubber in the Butterfly line up. When someone uses something like D09c and like it, D09c creates a feeling of safety that is hard to beat when you put in effort. But there is also a speed loss and a spin loss that comes with that speed loss on *some* shots and that is the effort you need to use to overcome it.
Zyre for someone who uses D09c or sometimes even D05, requires some adjustment. You initially think it lacks spin because you are trying to generate spin with it using the same topsheet approach as D09c or D05, But there are always shots you hit with it in the first 1 or two days of using it that show you what the rubber's potential is when the ball enters the sponge. The serves are faster and spinnier with smaller motions (so people who do reverse serves for example will fall in love with what they get from Zyre from far less effort). The challenge with Zyre is that if you have a certain approach to safety from using Dignics or other rubbers with thicker topsheets, it is hard to feel equally safe with Zyre on those shots, at least at first, because you need to feel the ball in the sponge more because the topsheet is so thin. But often with some practice, you get there and then you can use a reasonable blade (sometimes slightly slower than you use) to make up the difference.
Many people will prefer Zyre on whatever side of their paddle they don't generate relative power on. The spin and speed it creates when you get the timing right is phenomenal. With practice, some people want to recreate the same feeling on both sides of their paddle. But some people just don't like driving without a seatbelt and want to use D09c or even D05 and generate most of the effort themselves.
But when someone says a rubber/blade is too fast for the majority of people... while this might be true, it is often besides the point. A rubber/blade can be relatively too fast for how you should play and still enable you to play your style effectively. I have seen many players play great table tennis with blades that are too *fast* for their playing level, the thing is that everything in TT is adaptation and tradeoffs. If you train with Zyre, you might be able to beat players you couldn't beat before. For players who use slower blades like all wood etc, they might be surprised by what Zyre gives them both on offense and defense.
I will finish with this: it is not a rubber you can judge fairly without extensive playing experience with it. Some people just feel it is right immediately, but most people who like D09c or D05 go through adjustment periods, especially on generating slow heavy topspin.