Which of these four is the "best".
I've used three of them, the TS-590, the K3, and the Eagle, in demanding contest conditions at a variety of different stations. They are all fine radios.
I own and prefer the Eagle. I have 50000+ QSO's on mine in the past two years, including many scores in top-ten boxes in major CW and RTTY contests.
My preference for the Eagle is for simple ergonomics and receive audio quality under extended use.