Without wishing to reopen Pandora's Box, the retail version of the pt10, the Prestige Classic 600, has the same lovely flex as the pro stock. Where the pro stock is a remake of the retail or an older retail, similar racquet just made lighter.
Where the pro stock is a different layup (made differently or with different materials), it will obviously feel and play quite differently. This is also clearly the case if it is a different string pattern like the 260.2, it will play very differently from the retail Youtek Radical MP.. The 260.1 on the other hand, will feel similar apart from the weight.
In summary, the retail racquets have the weight more evenly distributed through the frame where as the pro stocks come lighter from the factory to be customised later, which is done generally with lead in the head and silicone in the handle. The modern trend is a 'polarised' set up, with lead at 12 under the bumper.
The silicone gives a lovely dead but solid feel where are some of the retail racquets with less weight in the handle feel less solid and hollow. The lead at 12 gives your rally ball a lot more natural shape and spin and hence margin for error. Most pros seem to set up their racquets this way. My Tipsarevic sticks on the other hand, have the lead at 3 and 9 which make them hit the ball well flat, not so much spin. Roddick also had this setup?
Your pro stocks can be set up however you like mostly, some like the Grigor Dimitrov 93 that was made for Fed are so heavy in the head even with no lead that there isn't much you can add without it turning into a club!
But most can be made lighter than the retail if you like with different balances than the retail and I think that with the solid feel from the silicone and the shape from the lead in the head is what attracts most people to pro stocks over retail.
The hairpins come longer than standard and can be cut to whatever length also. This appeals greatly to me, big fan of the longer sticks, seems to hit a ball with more power and spin which helps when you move like I do..
Some people prefer the weight distribution like the retail has and the weight of the retail, great if you do because they are generally cheaper and more readily available! My preferred specs are 340 strung, 27.5 long, balance 33cms with a flex around 60 and there aren't many racquets that are like that on the retail front, hence I tend to buy and play with pro stocks and get much enjoyment from trying the different ones.