Tiller questions?

Looking at a 60" John Deere model 660 Tiller, looks to be in great shape.
Question the manual says the tiller is for 4300-4600 tractos and NOT recommended for 4100-4200 tractors.
Also states PTO should be minimum of 25hp.

I have a 2720 CUT which is rated at 23hp and the JD newer tillers are 60" wide for this tractor.
Is this older model geared different that it requires 25hp PTO?
Is my 2720 too small to handle this tiller?

Also looking at new King Klutter and howe tiller for just a few $$ more?
What are you thoughts on these "china barnds"

I also found a used BEFCO 60" unit for a lot less money 6 years old, stated in Excellent condition stored inside -- Have not had the time to check it out?

I will only be using the tiller occansionally, garden spring & fall, and landscaping so I have a hard time spending lots of $$$ for a really tough top brand unit, however the lanscaping work I usually do is tough work of rocks and lots of clay in my area.

Looking for advise.;

Thanks