Actually, I tend to agree with you. Poly definitely does not provide as consistent a string bed as kevlar, and for bite? An 18g kevlar or Forten Kevlar Gear 17L put the smack down on poly. Literally, they just rip the shred off the ball. In fact, so much so that it can get annoying. When I'm hitting all out on my topspin forehand, often times, I literally find fuzz from the ball flying in my face...no joke. In conclusion, that is why the pros don't use kevlar? Because it ruins their after match smile.
No, actually, it's because the pros in my opinion, pound for pound, will hit the sweet spot more often than your average joe. Because of that they aren't as subject to the string inconsistencies of poly as the average person. Even more so than that, poly is simply easier on the arm. I won't say better feel necessarily, they both have their charm, and I actually think kevlar has a nice feel in its own unique way, a very fibrous and organic response for me that I like. However, the big difference for me at least, is that I find kevlar can sometimes send a noticeably more jarring response up my elbow, it feels like someone just sent a sharp, long, thin needle up my elbow veins and hit ye old funny bone making me curse out loud and swear I'll never go this route again.
But, with that said, it's hard to argue with the results. I really think if you hit a lot, it's best to string kevlar very low as a result. The great thing about kevlar for me is that the properties are much the same at every tension, wheras poly verys wildly. Strung loose, poly gives me an unsure feel, slipperly like an eel on my bad days, and I'll start spraying balls. Strung tight, poly too can begin to feel board like and jar the arm. Overall, I would say that Luxilon Timo 18g is the closest too feeling like kevlar for me. It's a great string, but really don't get what it has that kevlar doesn't. To me, they provide the same thing and everyone talks about how great for control that stuff is. I.e. Both are very predictable strings that if not careful with the tension can jar the tendons. However, in terms of price timo is like twice the cost.
My problem with Ashaway Crossfire is that while it is unquestionably the best feeling kevlar, and by far the easiest on the arm, I don't find it as durable as a non-braided kevlar. In terms of 18g kevlars, I think I'd struggle to keep Ashaway Crossfire from breaking on me within the first 30 minutes to hour. But 18g non-braided kevlar, I don't doubt that it would last me alright.
Feel and ease on arm, though, no question, Ashaway Crossfire is the best choice among kevlars, and as long as you don't use their 18g version; it'll last you more than long enough.
As for the pros, getting back on topic for a second here, I think a lot of them are copy cat pros. It's just become the trendy thing to do. If a few people start calling poly the gospel, then everyone starts to too. I've always thought though that gee, what does this do (regarding polys) that my old kevlar hybrids don't? In reality, nothing. Objectively speaking I know that. The only two things are better comfort and pop, and also maybe a few more style points.
And ultimately, I think it really does boil down to just those three things. Poly is like ice cream being extruded from a frozen yogurt machine, it comes in all kinds of colors and flavors and slight differences. Kevlar on the other hand is pretty much kevlar for the most part. Playing with that makes you feel like you're married to your work and going to work for the man. It's drab and oppressive to look at it's royal browness for extended periods of time, as you find that month after month, it just keeps on unraveling and unraveling, but never breaks!!! It can be maddening.
(but that's just my own personal bias)
In terms of actual performance though, I think it just comes down to comfort and pop. At lower tensions especially, poly can give quite a bit of pop AND spin. I just think the pros are good enough about hitting the sweetspot to feel like they can bring the ball back down into the court AND they still get the "big bang" benefits, pardon the pun. Poly in other words is a more dynamic performer. Add to it, that it's much easier on the arm over the long haul, I think you have your answer (i.e. for me at least, I'd always break into really bad tennis eblow if I used kevlar for an extended period of time, despite playing really and confidently with it...so it was always a trade off).
Also, at higher tensions, this effect becomes magnified. There are a lot of pros who simply prefer the feel of a boardy string bed. For these guys, kevlar would be too harsh I think over the long haul so they hybrid it with gut in the crosses, and string tight, and wala you get a great popping sound and resonse, a lot of liveliness, yet you also get very good control and predictability as well. It's a great compromise. For me, it's polys great ability to hybrid well with natural gut that makes it great. I really don't like the way it feels at lower tensions, but with gut in the crosses strung tight, it's simply awesome for me.
That said, I would never want to put gut in the crosses with kevlar. Gut's ridiculously expensive (to me at least, I remeber snapping $30 Pacific top of the line stuff, 16g, in 45 minutes in my Prestige Classic and screaming...ye-ouuuuch!!! the agony that hurts!!!) and I at least would be afraid to try gut in the crosses with kevlar. I feel like the kevlar would just grind into the delicate crosses of gut a lot faster than would poly.
With poly, usually, when you break early; it's because of a big mishit near the top of the head "snapping" the string. With kevlar, it reallys puts a sawing into the crosses. I either saw through the kevlar mains or the crosses when I break it. I find though, strangely enough, that my poly-gut hybrids last seem to last me a lot longer than when I just put synthetic guts in the crosses, weird. It's almost as though the little give of the gut, cuts down on the chances of the traumatic and sudden "snap" break when you mishit a hard ball near the top of the grommets with poly, but that's just something I've noticed with me.
