Racing games will overall be close this gen, as they will be nearly hitting the ceiling but especially from the latest vidoes Driveclub quite clearly looks better.

what makes you say that?

I think it will be hard as Gran Turismo will surely aim for 60fps, so you know potential visuals cut in half. Sure tools, SDK's, footprints will mature and GT will have a longer dev time, but it will be hard to overcome.

DriveClub is 30FPS while Gran Turismo is 60FPS. and Evolution are going insane with details. 

Where is the FH gameplay from?

Driveclub, the overall presentation looks much more realistic.

It actually looks genuinely wet, humid and dangerous to drive it, where as FH just looks like someone emptied a few buckets on to the track.

FH:
Road: wet
Everything else: dry as a bone

DC:
Road: wet
Everything else: wet

However, i'll reserve final judgement till both games are actually out.

Open world game vs linear track based game. Lol. Both look amazing.

@ bolded : that's not true, technically. I expect Driveclub to look better but FH2 should come close since it's the second Forza game on Xbox One.

From here: 

http://gearnuke.com/driveclub-vs-forza-horizon-2-raindrops-comparison-one-realistic/

Here's another Forza one: 

Be honest, you made this thread just to get some satisfaction in seeing a lot of people say "Driveclub" didn't you :), cause i think if you showed both those gifs to a 5yr old he/she will also pick driveclub.

@Banaking
Everyone always thinks polyphony won't surpass their previous efforts..... then they go on and do just that lol.