I'd look at a 6600 or 6620.
The 4400 is smaller, will cost almost the same, and get less done.
6600 & 20 have a lot of life left in them for parts and such.
Hydro is nice, you won't go back if you get one; but nothing wrong with the stick, get along just fine with one of that's what you have.
The 6620 is newer, a few better features, will handle a 6 row better; nothing wrong with the 6600, going to be older, less features, cost less.