Well, I was going to try and get some more time with this string before posting comments, but my initial impression based on about an hours drilling is as follows:-
Firstly, people need to put aside any preconceptions they have about strings because its characteristics of Monogut ZX aren't like any other string I've ever played it. Equally accurate though would be describing this string as having the characteristics of all sorts of other different strings rolled into one depending on how you hit the ball. It really is that unusual.
Initial thoughts are as follows...
Lift.
The BLX 6.1 95 18x20 is a pretty flat hitting stick. Have played with it for years. Balls tend to take on a fairly low trajectory over the net, even with a full bed poly. You really have to work the stick to generate a high ball trajectory over the net. I was really surprised how much 'lift' the ZX gave to the ball. It was very easy to generate more of an up/down ball trajectory even with that 18x20 pattern. Very surprised by this. It seems like the strings stretch and then spring back into place to put rotations on the ball, with the string's power giving the ball length and depth. If you want a 'high launch angle', its there. Equally, if you want to flatten out the ball, you can do that easily as well. There's wide range of variation that you can easily put on the trajectory of the ball.
Stiffness/comfort, string bed feel, and unusual sweetspot characteristics.
As mentioned earlier, I feared that I had strung this at too high a tension. Well, I was right and wrong in equal parts. The 6.1 does not have a very big sweetspot. It also gets smaller, the higher the tension you go or the stiffer the string that you use. The ZX accentuated those characteristics. Hit the ball in the middle of the sweetspot and there's ALOT of give. This string feels very soft and buttery right in the middle of the stringbed. It's like the ball really sinks into the middle of the stringbed and then springs out. It's a pretty plush sensation and there's alot of power from the stringbed there. However, when you don't centre the ball and instead hit outside that center sweetspot, its unforgiving and the power dies. It feels slightly boardy/tinny when you hit outside of the sweetspot (though it could the symptom of the tension I used). But at no time were the strings uncomfortable (despite them seeming like a washboard off the stringer), no matter what part of the stirngbed you used to strike the ball. The difference between the middle of the stringbed and the area of the strings away from the sweetspot / towards the frame is
very marked in terms of difference in power, 'give' and forgivenss. There's a very big range of difference going on here (though it may have been due to the tension I used). It's a very unusual characteristic.
Power.
Vast difference between the centering the ball in the sweet spot and anything immediately outside the sweetspot. Nail the sweetspot and you can boom the ball. Anything outside the sweetspot and the ball dies. ZX seems to accentuate the characteristics of the 6.1 stringbed which isn't generally that forgiving. But my soft polys don't perform like that - obviously there is a difference between inside the sweetspot and outside the sweet but the different is nowhere near as marked with the soft co-polys (BHBR16) that I usually use with the 6.1. With the ZX, the differenced in power between inside the sweetspot and outside the sweetspot is very marked. The Monogot ZX seems to reward good technique. Hit the ball well, and that power from the middle of the sweetspot is controllable. Mis-time it, for example, hitting the ball too flat when jammed on a return and the ball lands 3ft behind the baseline.
Comfort.
Very comfortable string. There's alot of give to it. Ball feels like it really sinks into the stringbed before springing back out. Complete opposite of a stiff poly like Luxilon 4G.
Spin.
The jury's still out on this I'm afraid. Really need some more time with the string, but I didn't feel like was hittng a poly-esque heavy ball. There was ball speed and depth, but my opponents seemed to be swinging away at balls I was hitting towards them, and sending it back aggressively, instead of it being me putting
them under pressure with the type of balls I normally hit with a full poly bed. In that sense, it seems to play a bit like a a multifilament or natural gut. But really I need some more time with the strings to figure this out, so its a tenative view at this stage because it could be explained by me simply getting used to the string and not hitting as aggressively towards opponents as I might usually do with a full bed poly and getting used to that high power central sweetspot in the stringbed. Need more testing time with regard to the issue of spin.
Power modulation.
Some strings allow for a limited range of power no matter how hard you hit the ball. For example, Babolat Revenge, Luxilon 4G, Weiscannnon Silverstring etc. Other strings allow for a vast range of power depending on how hard you hit the ball eg. natural gut. ZX has a vast range of potential power. You want to smack the ball through the court with a ton of ball speed, and you can do it (subject to being able to control it and keep the ball in the court). You want to take all the pace off the ball and hit the most delicate of drop volleys and you can do it. This is like having a 'big volume knob' that you adjust ad infinitum in terms power rather than a power 'on/off switch'. In that sense, its alot like natural gut.
Control.
Bit too early for me to be definitive about this but I didn't feel that the string was uncontrolled, provided you hit with the ball with good technique, either with a low>high path or turn your hand over through the stroke. That said, my comments on control may be influenced by having strung it in a control orientated stick. As mentioned earlier, if you're late hitting the ball and don't put some topspin on it, it can fly because of its inherent power. Its not forgiving of crude strokes or wild swings that a lower powered poly would be. It rewards good technique. In fact, I'd suggest that good technique, footwork/positioning and timing is a pre-requisite to get the best out of it. It doesn't seem as wild as some high powered multifilaments I've seen but again, that could be due to the racquet it was strung it. I have to admit that I don't think I've ever strung with the 6.1 with a full multifilment, so I don't really have a point for comparison. Directionally, the ZX seems pretty precise, but I qualify that again mentioning the racquet that it was strung in. Need some more hitting time with it, as well as probably trying it in a larger headed, open patterned stick. I suspect though that its unlikely to suit something like an APDC but I could very easily be wrong because its an unusual string.
Feel
This is a hard one to describe. It's soft but not soft. You can feel the ball but its not like the feel that you get from a multi, a synthetic gut or a poly. The stringbed sort of 'gives' and the ball sinks in but with a sort of a plasticine 'give' to it. It doesn't feel like other strings. Its a long time since I played with full bed natural gut, but from memory, I think its a bit like 1.25mm VS Team. The harder you hit, the more it seems to give before catapulting the ball out again. But then, it doesn't feel like natural gut either - it doesn't have that elastic spring - its more like a mechanical spring. It's hard to describe. All I can say is that it has its own unique feel.
Volleys
Volleys were good in terms of feel but adversely affected by that differential going on between the middle sweetspot (soft/plush) and the area immediately outside the sweetspot (slightly boardy/tinny/power dying). Again, it may have been a mixture of the the string, the tension used and the 6.1 small sweetspot producing slightly unforgiving results on anything less than perfectly centered volleys.
Durability
The string didn't break on me during play, but I only played for an hour or so. That said, I did manage to snap the end of the string off when tying off the last knot during stringing despite pulling in the direction of the knot. I doubt that it will have the durability of a poly.