What they are: NYXL strings are a comparatively new offering of electric guitar string offered by D'addario.
What they claim:
D’Addario NYXL guitar strings will bend farther, sing louder, and stay in tune better than any string you’ve played before. Envisioned, perfected, and manufactured by D’Addario in New York, this newly engineered, break-resistant, high-carbon steel core and plain steel alloy delivers a whole new level of freedom, confidence, and power. NYXL’s provide more strength and up to 131% greater tuning stability by utilizing a completely reinvented wire drawing process coupled with a revolutionary “fusion twist” process for the plain steels. The reformulated nickel plated string windings have greater magnetic properties resulting in higher output and enhanced mid-range frequency response for more presence and crunch.First impressions: Well, our first impressions of the new strings are a little... out of memory, but we'll cover what we can here. We had an interesting first experience with the strings, that involved cutting the high E too short. In reality, this actually put these strings to a good first test regarding stability and breakage, yielding great results.
At the time, the strings were in nearly no supply whatsoever, as they had not yet officially been released, and we suspected we may have to transplant a high E from another set. Surprisingly enough, this was not the case, and once we got the string to catch the tuner (this was quite the process with a lot of trial and error, and also not something I want to go through again.) Not only were we surprised that it held up, but upon tuning it the first time, it stayed. No slippage, no break in. Also an important note, the guitar in question had gone from an extended test run of Ernie Ball cobalt strings to the NYXL set, with a night and day difference. (more below)
What we found after using them for some time: Now, my Les Paul has been something of a case queen. Not a particularly high end model or anything, but when you work in a guitar shop, you find that occasionally some of the guitars you've owned for some time get a little less love than they're used to. But it often sees gear testing use in store (for amps, pedals, etc.) and, in this case, was a good string seller. We used it to give people a look at the strings that have already been in action before they bought. At $12 for a pack, we figured it was a good idea to keep a set on hand in use if there was ever any question of quality. Test runs unplugged helped focus on the feel of the strings, and with an amp, the clarity and output. And the more they were passed through customer hands, the more we could say they were holding up to use. The strings pitched themselves every time.
How they compare: The only current direct competitor set on the market that I have personal experience with is the Ernie Ball Cobalt line. The main selling point of the Cobalt line is, and has always been, increased output. They are BRIGHT, they are at times shrill with the wrong setting, but are best represented in a dark guitar in a setting that might otherwise sound a little muddy. And if cost is your issue, Cobalts may be your thing, being typically a few bucks less. Unless you're equally after a smooth string feel with your increased output, in which case, NYXL is king. No question.
Things you need to know: NYXLs are very temperamental when it comes to hand sweat and anything that gets on the strings after playing. The most consistently maintained set we have used, due to passing through a lot of hands, held up the longest, while current production sets that we are currently using are lasting between 2-4 months on average. These guitars, to be fair, are being played on a daily or weekly basis in varying humidity and temperatures, while our test set may have been out a few times for a few minutes every week or so, and then being cleaned each time. We have only received one mention of a string breaking with suspicion that it was potentially a guitar issue due to breakage in the same place (sharp edge on the bridge, etc.).
One more thing: It would be a reasonable question to wonder why, if the strings were in good condition in both feel and output, why would I feel the need to change them? The simple reason: the guitar in question is now currently being employed in a band setting, with a tuning that the standard set would not easily accommodate for. They have been replaced with one of the sets from the second NYXL release "wave" that featured thicker gauges for non-custom sets, plus gauges, and balanced tension options.
Overall: Looking at the strings from a completely objective angle, the strings are a fantastic step in the right direction for the industry overall. They are an answer to the EB Cobalt line and solve a lot of the problems cited about them regarding feel. They are a great investment, particularly for guitars that don't see a lot of play time, and for players that typically take standard maintenance measures for their strings. Your mileage may vary.