If you get AmiTCP it is going to be a ride full of pain to configure it. But it does the job pretty well.
Genesis is acceptable, easy to use, but a bit buggy.
Miami Deluxe is great in many aspects. simple to use, supports DHCP, but it is not on sale anymore. So unless you get a second hand registered copy or a pirate one, you are doomed. The only drawback of Miami Deluxe is that it needs a beefy system to operate correctly, if not, you will get slower conections than both Genesis and AmiTCP.
Termite TCP is a nice antique, simple to use, that does not support ethernet conections, seems only designed for dialups.
I never tried, and never seen in the wild the other TCP-IP stack available, Interworks I-Net 225, so I cant comment anything on this one.