I personally don't have any experience with these tree saws, so keep that in mind. I'll just give a "synopsis" of what I've read on here, found from other online research (on the internet, so you know it's true

) and speaking to the manufactures. I've also been in touch with other members by private message and they've given me their thoughts.
For your tractor (very similar to mine but with more PTO hp) the tree saw would work very well. It seems like most are saying that for any trees under 8" it will cut them pretty much as fast as you want to back up. Anything over that, starts getting a little slower. Even a larger 70hp tractor could use more power when cutting into a large tree. If you have HST transmission you will be able to creep into the cut as slow as needed if it's a larger tree.
If you have very hilly terrain, or very rocky areas, (which I'm assuming you have neither in TX) then that could pose a complication to the overall efficiency of the saw.
If you have rear remote hydraulics, you can get the grapple version which is very useful to apply pressure to the tree as it is about to go over, decreasing the chances of dropping a tree on the tractor. Although the website says that the grapple is very useful for hauling the trees away after you cut them, it seems like it's not as practical as they make it seem, unless they are smaller, bushier trees. I personally wouldn't use it for that, since I have a front end loader grapple.
Honestly though, if most of your trees are 18" plus, then I do NOT think that a tree saw on a relatively small tractor is even remotely close to resembling a good idea.