I currently own Ultra II (braided with boron... 2nd from left in the picture provided in an earlier link) and PS Original 85. I play with both of them as I see fit.
You need a big arm and swing to hit with Ultra II. If you are accurate, the racquet will plow through anything and get your ball where you need it.
In my recent plays, I realized that I am not as young anymore and the racquet causes some arm pains.
ProStaff is my ALL time favorite. I am still trying to find a replacement. It is all about control and feedback. Pinpoint accuracy is how I would describe. Now as heavy as Ultra II but it will still plow through if you have the full swing (I do).
Although I do not own anymore, I also played for long time with Prince Graphite Original Mid (93). The most powerful of the three. It had a "ping" that was so pleasant to listen and easy on the arm. Great for "crowd pleasing" shots and "volleys" (when compared to Wilsons).
With ProStaff and Ultra II you can not be late for any shot or your returns will be punished by your opponents.
With ProStaff and Ultra II you can not misshit (or miss the sweetspot) or your returns will be punished by your opponents.
With ProStaff and Ultra II you will generate "untouchables". Extremely accurate and deep balls that have low bounce. I call these "snakes". They are not the current generation's top spin, crowd pleasing, a foot over the net with a nice bounce shots. But they are 3 to 5 inches above the net, deep, with a very low bounce, untouchable point generating shots.
Overheads, are no brainer as long as you are ready and timed your shot well.
When the subject is backhand, both Ultra II and ProStaff makes you like Sampras or Federer (for single hand hitters).
Prince will allow you generate more spin loaded shots. I always thought that Prince would probably have been easier to my game. However, when I have one of those short balls where I run 5-6 steps and I get my bottom as close to the ground (as I can) and swing one of those "you should not be doing this when you are so close to the net" shots where the racquet head is swung and closed so fast that if you did not know any better you would have thought that I am fighting with a bee. I never miss them with my ProStaff. Tangent to the net, deep, and ego rubbing. I was never able to generate those shots with Prince. Which actually means nothing other than the fact that I probably should have slowed down my swing and generate an underspin approach. However, I always felt that I was having a harder time to close Prince's head when the balls were above average speed, and I would retreat to a more defensive game. I tried to play with my timing but I failed.
Prince would also compliment spin serves if you have it. To me, it never felt as steady/stable as my ProStaff for power serves.
I have an eastern grip, full swing with body turned to the ball on both forehands and backhands (single handed).
I hit hard on both sides. I love to hit paralel and short cross court (inside the serve box, close to net) forehands and backhands.
I serve a strong flat first serve, and strong very little spin added second serve (thus I am quite prone to double faults).
I am lefty.
I have 66 lbs 17 gauge on my ProStaff.
I have 63 lbs 16 gauge on my Ultra II.
Both of them have brand new grip.
In general, I would with people where points are not really the main drive.
So for what is worth, obviously these are my personal opinions. I am not an expert. I just love to hit the ball.
Cheers,
MrName.