Like I said, I own a PT. The big one. I am not biased, though. If I had found a tractor that would exceed 20 degrees sideways on slopes I would have probably jumped at the opportunity.
The PT is not for everyone, and you don't see any PT owner getting into a conversation about it being a better machine than a normal tractor until you have people asking on two issues, one being slopes, and one being manueverability. The small PT is a fantastic machine for tight spaces. It is very powerful for its size, and has tons of attachments making it very versatile. Given its engine, in manages slopes well.
As for slopes, unless you have big bucks, the larger PT is probably the best machine you are going to find, and one that is going to make you feel incredibly comfortable. My wife is a very fearful person. She visualizes the worst possible scenarious of anything and then talks herself out of tons of great experiences. The PT is the only machine I have seen her get on where she jetted down the slopes, cut across sideways and came back up saying it was no big thing.
You might be able to make a CUT work, but given your description of your slopes, why risk it. One bad bump and over you go. Now maybe you come from a line of race car drivers or others who are fearless and know how to respond in an accident (seatbelt on, keep your hands inside and don't try to catch yourself when you roll over). If so, the cut is going to be easier to get serviced, and easier to purchase used implements.
Will a cut work for your needs, maybe. Depends on how much you are willing to give up (how much of your sloped property you do not want to maintain, at least with the tractor). It actually might not be a bad thing, you may go from 15 degrees to cliff and well, the PT would be no better than a cut. But if you want to get serious about the slope work, get a machine that is designed for the slopes. There are a few others like the PT, but they are european, hard to get parts for and very few distributors but very well made machines.
Finally, as I said, there are some quirks to the PT you have to be prepared for. The biggest is that there is no dealer network. You order straight from the factory, and all your parts come from the factory. You need to be comfortable turning a wrench as they have more working parts than a normal tractor. Or you need to have a friend who is a mechanic. They are easy to fix, and when you start to dig, you will find the parts are mostly off the shelf and you can purchase locally.
Oh, you said you felt the machine is loud. Hmmmm... It ain't quiet, but I have never been on a tractor that is. It has a whine to it which is a bonus noise, they hydraulic pumps have a personality. But the engine noise is normal.
And as for ground clearance, there is a lot more of it than you think. Unless you are doing some seriously bumpy ground (like building large moguls for a ski resort) you are not going to have a ground clearance issue.