I agree with Bob.
They are very different animals. I have the 1445, which is closer to a skid steer (4000lbs, 45HP, 7' lift) than the 425, but even the 1445 is a long way from a skid steer.
Skid steers tend to have high lift, high power, especially high power hydraulic PTO/Aux, and are very compact. The downsides include their tendancy to tear up the ground, their high center of gravity, and general instability.
Skid steers also tend to be able to put all of their hydraulic horsepower to the task at hand, which gives them better dig in force, and better lift force. PT split the load between the PTO and the drive motor, so you will be able to do both. That is great for mowing on a hillside, but not so great if you want ultimate power to
a) dig in
b) drive an auger through rock
c) flip that boulder.
As an example, the 1445 has a 15gpm @3000psi PTO, which equates to about 27HP hydraulically, leaving 18HP +/- for drive horsepower, even at maximum hydraulic load.
But frankly, I wouldn't take a skid steer off of a basically level job site. The 1445 can climb 25-30 degrees (depending on traction) and can do a uturn on a 25 degree slope. I'm not saying that I find it relaxing(can you say "pucker factor"?), but the machine is rock solid and stable- which is why I bought the PT. If I can get the tractor out on the slope, I can get work done; if it sits in the barn, it might be great for impressing the neighbors, but it isn't earning its keep as a tool in my book. ("it" being a skid steer, D4, N-9, or that old Unimog.)
Just my $0.02...
All the best,
Peter