If you are thinking of buying new, I wouldn't do it again. But those were better times, when I bought my Magnatrac 5000. I have the all hydraulic version, with the 6 way PAT blade, 3 point hitch and PTO. 25 HP kohler engine.
As far as pushing out trees, not very big ones, maybe 2-3". Don't cut off at ground level, or you won't have a lever to work it out with. What mine excels at is tight spaces and drainage ditches. It don't move real fast, 2 MPH regular speed, 3 MPH overdrive. When I bought mine, the ASV RC30 rubbertrack loader hadn't come out yet.
Price, speed, track type, and HP considerations plus the # of attachments for the ASV, make it the better choice. I still Like the struck better, but it takes so long to do anything with, it gets a lot less use than it used to. It will still go on impossibly steep slopes, and push a full blade of dirt, just like a big cat!