I find Power Tennis superior to Final Match Tennis eventually.
World Court is very arcady unrealistic, and too cute for my taste, besides: 90% of the player's sprite being the head makes it kind of hard to judge where exactly on the court the player sprite stands. And it is graphically butt ugly. The sound is equally bad. My least favorite of all Namco games on the PCE.
On Davis Cup (which I would love to love if it weren't for the angle of view) I have a question:
So far I only knew it from the ROM, but that is the US version. In Japan it was on CD - are there any actual differences to gameplay/modes, etc., or did they just add music and other "fluff"?