Honestly, at E3, all three were very impressive (adding PCARS2 into the mix). I wouldn't call any of them bad looking, and I think anybody that does is likely blinded by a heavy bias. It's different levels of impressive too; GT Sport looks stunning in a hyper-realism sort of way, and while neither of the other games can quite match its smaller details, they both have dynamic time/weather. Seeing
that in motion is very eye-catching, in a way that GT Sport, with its static time of day, just can't match. Swings and roundabouts.
WRC7 looked pretty great as well, but that
may have been slightly influenced by the awesome motion rig it was running on!*
* (just kidding: we tried it on a regular screen and it was good there too).