Played 3 sets of doubles and 1 set of singles over 3 hours, here are my initial thoughts of 89t. Since most of us have already known of the plus points of this racket, I will just focus on the comparison between 89t and Qtour.
Stability: If I have not used Qtour before 89t, I will definitely find 89t's stability pretty special. However, Qtour's stability is quite outstanding as well, so I will think they are much on par with 89t giving a bit firmer feel.
Power: Qtour has much more power where you will not get penalized as badly as 89t for hitting a short swing when you are not in the right position or when you mistime the ball. The sweetspot of Qtour seems much bigger to me as 89t really forced me to focus on every shot to hit in the centre of the frame. On the whole, Qtour just feels much more forgiving to get the decent depth and power.
Control: This is where 89t has the advantage over Qtour. Being lower powered, 89t offers better control at the net and groundstrokes, provided you have well controlled long swings. Sometimes, due to the low power, you may just end up losing control of the swing when forcing the issue. This should be less of a problem for more skillful and stronger players.
Serves: Both rackets seems to be equally capable for flat serve with good accuracy. Slice and kick serves are decent for me, nothing as spectacular as some of the open string pattern rackets that I own like BC20 and Donnay Pro1. I do have to put in more effort to serve with 89t though.
Slice: While I am able to keep the slice low with 89t, I struggled with getting the depth especially when I was defending with the slice. Again, I have to say Qtour allows me to defend with the slice on both side a lot better.
Spin: Flat forehand with 89t is the money shot, but Qtour is no slouch in that department with its 18x20 string pattern. What I feel that it is lacking in 89t, is my ability to hit heavy balls with spin. Most of the balls which I tried to hit with more spin, either fell short or just lack in the speed department. As a result, I ended up hitting flatter balls most of the time. Qtour on the other hand I feel, offers the extra component of heavy deep spinning balls.
Comfort: This is the surprise here, I actually found 89t more comfortable for my arm than the Qtour. As for my shoulder, not much difference as both rackets weighs almost similarly at 357 to 359g, so same bit of soreness in my shoulder after the session.
Overall: I feel that if one is skillful (able to hit at the smaller sweetspot of 89t most of the time) and strong (to be able generate power with full fast swings over 3 to 4 sets of competitive tennis), then 89t should be a better choice as it offers better control overall. For the rest, I will say Qtour is a more forgiving racket and will probably allow you to play more effectively. Anyway, this is just my humble opinion. Most importantly is that you play what you prefer and enjoy most.
(One last note, I'm not ready to give up on 89t yet after just 3 hours. I will probably lower the tension further to see if it could improve things.)