As TripleR indicated, it is much easier to get around trees and obstacles with a MMM. It is much more like operating your current tractor. The Rear Finish Mowers (RFM) behind the tractor swing wide when you turn so with the amount of trees you have, that is a factor. Advantages of the RFM are, you have a lot to choose from as to brand, quality, and size, they would generally be cheaper to purchase, and they can be removed and re-installed easier. Taking a MMM off of my tractor which is similar to the 2520 you are looking at probably takes 5 - 10 minutes. Removing a RFM is probably 1 - 2 minutes. You do not have to remove the MMM to use the loader or do other things. If I was driving around picking up limbs in the yard I wouldn't bother but if I was going to be grading the driveway with the box blade, I probably would, but not absolutely necessary.
As to which of the two to buy, Artesia Aggie did a good sum up for you. If you are going to be doing a lot of larger projects where the power and strength of the 3032 would be a benefit, that is probably the better choice. If it is mostly maintenance, mowing, grading a drive, bringing in some dirt and spreading it, etc, the 2520 might be the better fit.
I live on 3 acres, but also have 12 acres which is much rougher. On the 3 acres, the Kubota
B2920 that I have is more than enough and I would not want something bigger for what I need to do on that property. On the other property where I mow with a brush hog, drag trees, move some pretty big rocks, etc, I would opt for a larger tractor if I was going to be there all the time.