When Perlick switched to the 525 design, the "feel" of the faucet really changed. They basically reduced the overall cost of the entire faucet by eliminating the shuttle/plunger that sealed the faucet when the handle was pulled back and forth. Now, they simply attached a ball to the end of the handle which does the sealing. What really changed was the throw distance of the handle itself. Before, only a small movement of the handle was required for full open to full close. The 525's are about double the throw of the 425's and it just makes the faucet feel different. Don't get me wrong, I think the 525's are fine, but I like the action of the 425's better.
If you can score some used 425's, I would recommend those before the 525's. Look around, you might be able to find some. I agree with the others that the creamer function is overrated and not worth the expense.