I had a few games last night and here's what I thought.
My first impressions, as they were with the demo, is that the graphics are a little disappointing, it's difficult to describe but it is very pixelated and when playing in cockpit view the brightly coloured/flashing edges are a little distracting. The indy car track from the demo is really bad, the fences and tracks look like a blocky mess. Even the 2D cars in the menu look like something from the last gen. Having said that some tracks look a lot better and it is very smooth. The 3D cars and photo are much better and the photo's you can produce are really nice.
Racing in the wet is good and the puddles really impact your driving as they should. However they are always in the same place and stay the same size no matter how much is rains or if other cars splash through them just before you, a dynamic rain/weather system would have been nice as although this looks nice it just isn't a proper dynamic system.
I had a few races online and that worked fine although I've not played enough to really make a judgement on the overall multiplayer experience - thats something for the weekend.
The AI Drivatar is OK but very inconsistent no matter what difficulty you choose, sometimes you can find you'll win by a mile or on other occasions you'll get a drivatar that is just simply way faster than any other car no matter how well you drive and that can happen even on the lower difficulty. This can mean that you don't get the close fought races you'd like and therefore a lot of races can be either boring or frustrating.
The events, although I can see why they did them, can seem out of place and spoil the flow, especially some which are just boring..
I still don't see the point in the Mod Cards, just seems like something that's been added for the sake of adding something but I may get used to them, the random payouts are also questionable I think.
Overall I'd say I like it but having been playing Project Cars on the PS4 over the recent months this just doesn't have the same impact as it once did, it's visually no where near as good and now feels a little to arcade in comparison. If you like Forza then you'll like this but the competition has taken the shine off it.