Those tree pullers work OK on a little tractor, but don't have big expectations. I bought one for my L2501. There are many variables on the size tree that you can pull up with it, which has pretty much been mentioned already. In short, you will probably realize you will not be able to pull up anything very big with it it. I do not regret buying it as it can be used for posts and even grabbing stuff. The picture of the tree pulled is really bigger than I can pull up most of the time. That one was in wet soil, so it came out without too much work.
I have found that my root grapple can get out a bigger tree fairly easy. If I can push it over, I can work it back and forth and get under it and pop it out with the grapple. It is best to push it over, cut it off about waste high. Move the cut portion out of the way and then work on getting the rest out of the ground by pushing on it from different directions. Grabbing a pushed over tree still in the ground puts uneven force on the loader/grapple..