Forget about BG66 since you've BG66UM and NBG98 in your consideration. BG66UM (MEDIUM FEELING) REPULSION - 10/10 DURABILITY - 6/10 HITTING SOUND - 10/10 SHOCK ABSORPTION - 8/10 CONTROL - 10/10 NBG98 (MEDIUM FEELING) REPULSION - 10/10 DURABILITY - 7/10 HITTING SOUND - 8/10 SHOCK ABSORPTION - 8/10 CONTROL - 8/10 For your information. Durability NBG98 slightly better than BG66UM. Overall BG66UM wins. But i personally love NBG98 more. Get a chance to try both. Since it's not so expensive for a try. If you match racket with colour string. BG66UM has much choice of colour to match with.
I've used both strings on the same rackets and same tension. nbg98 lasts a bit longer but i feel it loses it's tension more before breaking. I got more fraying and movement in the mains on the nbg98 compared to the bg66um before they snapped. I've only used bg66um a couple of times so your experience may vary but that's what i've experienced so far. I'm using bg66um on my main rackets now. They feel stiffer than nbg98 when freshly strung too. Felt a bit harsh for me but settled fine after 2 sessions. Thinking i should lower my tension with bg66um. Personally, I favor nbg98 slightly over the other for comfort and being a bit more forgiving.
forget BG66 if you have your hands on 66 Ultimax or NBG98 also if you can afford to restring every 3 week or so. Its no problem. After ~3 weeks, its a dead string, can't really play AT ALL. Any other string would play better than 66 Ultimax after 3 weeks old. Its that bad. But within 3 weeks, its amazing. Many people would agree with me on this. Even a bit too bouncy (too much repulsion) for my taste.... NBG98 doesnt have that problem, last a bit longer too. I play 3-4 times a week (3-4 hours sessions) and i love smashing, so 66 ultimax only lasts around 2-3 weeks, after 1 and half week, many mains and crosses started to fray all over the middle of the racket. Anyway, i dont use 66 ultimax anymore since they turn out too expensive in a long run. Though they have so many good colours to match your racquet. bloody Yonex !!!
In my view, BG66UM is good till 26lbs. After that it becomes a hard wall with not much repulsion. On the contrary, NBG98 comes alive after 27lbs and above, but you need to use the first 1-2 times to "wear" down the coating. You'll get a crispy "ting" sound, though the 66UM is sharper. At my current 29lbs, i am enjoying it.
But Lining No 1 early tension drop is too big. I can't even imagine how much lbs should I try to match my actual tension, like I prefer to play at 25 to 26 lbs but when I order 28lbs (as I know it has huge early tension drop) it got dropped to 24 lbs the next day even before playing.
