I have been running the Toyo Proxes ST 255/45/20 tires for about 23k miles and they are terrible in the rain. My next tire will not be a Toyo.
I have decided to try the Kumho Ecsta ASX tire for my next tire.
Kumho Ecsta ASX
The best rain tire is probably the Pirelli Scorpion Ice & Snow tire.
But they are expensive.
PIRELLI - CATALOGO CAR - Scorpion ICE&SNOW