Ok, I've played with the N50-III for about 1-2 weeks now (5-6 sessions).
Amazing racket. Again, I feel that it's just so easy to use. Quick on defence. Decent power on attack. I think the holes on the racket really help in racket head movement through the air. It really cuts through the air and this helps in both defence and attack.
It's quick at the net as well. I am able to perform intercepts and drives very well. Net shots are also really good and the feel is there despite being a slightly head heavy racket. On the attack, my shots also seem faster and this is definitely aided by the flexible shaft. Placement and angle is also good and drop shots are very accurate. I don't recall having so many drop shots hitting the white tape and going over. I've had many of those since I started using the N50-III.
The problems I had on the forehand defence seem to be gone now. I'm beginning to feel really comfortable with the racket in both attack and defence. Transition between defence and attack remains as quick as ever.
Possibly the best racket I've used to date. And the rackets I used prior to this one were the Yonex Arcsaber 9FL, Wilson Zonar BLX and Kason F9.
I feel that I can now come up with /10 ratings for the racket in several departments.
Attack (e.g. smashes, attacking clears, fast/steep drops): 9/10
Power is accessible but sometimes it can feel like the racket just lacks that raw power. It does not feel like a MEATY racket (e.g. Yonex VT80) and I doubt naturally hard-hitters will like playing with the N50-III. Fans of the VT80/MX90 would not like the feel of the N50-III. They're just different.
Defence (e.g. blocks, clears): 9.5/10
It's a fast racket, no doubt. Glides through the air and placement of defensive shots are also good.
Counter-attack (e.g. counter drives, transition shots): 9.8/10
This is where the racket truly shines. The ProMaster label really suits. I feel that I am able to play a counter-attacking drive into empty space and play a winning smash right after. It possesses the essentials for both attack and defence.
Overall feel/placement/ease of use: 9.7/10
Flicks and double-motions are great. Shots come off accurately and overall, it is an easy racket to use and I believe it would suit all-round players in addition to counter-attacking players. Perhaps not the best for the all-out smasher but these days, badminton is not all about the smash anymore!
Price: $$$/10
Without a doubt the most expensive racket I've ever purchased and it definitely leaves a hole in the wallet. Clashes make my heart skip a beat. A broken N50-III is a dreaded nightmare. Is it worth it? I'm enjoying the racket so far. It does have a quality feel to it and new tech like the AirStream system are really innovative as far as I'm concerned. But it may just be a bit overpriced. If it were priced around $170-190 then perhaps Li-Ning would sell a fair amount more. >$200 just feels pricey. But maybe that is where badminton racket pricing is headed (not so different to tennis rackets). The latest rackets from Yonex don't come cheap either.
Singles/doubles/mixed: maybe all!
I'm yet to play a game of singles with it so I cannot form an opinion on that yet. It's a great doubles racket, quick on both attack and defence and doubles is all about speed. The all-round nature of the racket also helps a lot in mixed doubles. For me, mixed is about having a wide repertoire. The racket in my opinion, acts as a great tool to tap into your skill sets.
To those who are still on the fence about the N50-III, my advice is: if you can afford it, try it.