Thanks for the comments. The cost was a little over $9K including tax and a small shipping fee. I did the assembly myself which save a few hundred dollars, took about 4hrs.
Right now we are running it on dad's 5045E (38hp) and it handles it pretty well. The electronic Auto-feed is what makes it usable on a smaller tractor. It only feeds the material in as fast as the tractor can power it. If the rotor slows down beyond a certain rpm it momentarily stops feeding until the speed gets back up. Stuff up to about 5" it pulls right through without bogging the tractor down, larger than that and it makes it work. Undoubtedly the 2550 JD would handle it better, but I'm also building fence right now and have the post driver on it.