So far I have been left with a bitter taste in my mouth and cannot recommend this game... yet.
Pros:
The graphics and optimisation. I have a FX-8320 and a GTX 970. I'm getting 60+ FPS with the whole grid on ultra.
The handling model. I have a G27 and I am happy with the FFB and the physics have vastly improved, especially compared to F1 2014.
Cons:
No safety car. I don't know Codemasters reasoning for this but I personally feel it takes away from the game.
This game crashes more than Maldonado. Ran a benchmark, crashed. Tried online, crashed. Started pro season mode, crashed. You get the idea.
Littered with bugs. For now there is only one that I find truly game breaking. When I play Pro season mode, (for those who dont know, it is supposed to turn off all HUD and assists and locks you into cockpit cam) I still have all the assists on and since the menu is greyed out I can't manually turn them off.
I would advise anybody interested in this game, to be patient and wait for future fixes and then consider a purchase.
May update this in the future. 10/07/15
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24 hours of game time later I feel it is time to update my review.
First off, since my first review they released a 2nd patch on the day of release, which is pathetic that it was even needed in the first place as it wasnt even a large one. Thankfully though it seems to have fixed the game crashing so Pastor can now sit safe and keep his reputation.
The more I have driven in this game the more and more I'm enjoying racing the AI and the handling model. The Championship season, Quick race and Time trial modes are the ONLY parts of the game I would consider ready to be released. Pro season and Multiplayer however were and STILL ARE NOT READY.
For the first time in the series you can actually race the AI wheel-to-wheel, and unlike Project Cars there aggresion is about right. The AI are very spacially aware so if you were to dive up there inside they won't turn in on you. They are also very racey themselves as they wont back out 100 metres before a braking zone as before, and will try to outbrake you if you leave the door open. For reference I have the AI on the hardest setting.
However I would consider Championship season mode ready,although it does have a few features missing. You can no longer underfuel the car in this game and since you can no longer run rich fuel mix for longer than half a lap before your engine overheats, I end up with around 5 laps of fuel left at the end of a 100% race. You can no longer fully customize your strategy before the race, you can only choose between preselected strategies given to you by your teams strategist and with 100% races, generally speaking you're given 2 options but if you qualify within the top 10 it's normally 1. My final complaint with Championship season mode is the inability to customize the weekend length. There are 3 choices and cant be tweaked. Short weekend- 15 mins practice, one-shot qualifying, 25% race. Normal weekend- 30 mins practice, one qualifying round, 50% race. Long weekend- 1 hour practice, full 3 rounds of qualifying, 100% race.
Quick race works as it should with you being able to actually tweak it to your liking and there's not much else to say. Time Trial has been improved upon now as at most circuits/corners the game is strict with you leaving track limits, but my new favourite feature is you can copy setups from people at the top of the leaderboards. I highly recommend doing this unless you want to be left alone and know what you're doing. My only problem with Time Trial is that at some corners you can still exceed track limits and not have your lap invalidated. Is it really that hard code"masters" to just invalidate laptimes if you exceed track limits with all 4 wheels regardless of time lost/gained?
I feel the need to mention at this point that the F1 2014 season is also included in this game as I'm rather neutral to its integration. Albeit a nice bonus, I bought this game for the 2015 season and would rather have had them focus more time on the current season than the previous one.
The problem with Pro season mode mentioned in my first review is still there and upon further review I think there was no real need for Codemasters to even add this mode as you can change your HUD, assist and camera angle in Championship season mode to the exact same settings.
Now the real big-hitter that is Multiplayer. Blandly put, the multiplayer is a mess, there's no two ways about it. From unpredictable ghosting, to desynchonised lobbies, to driving through pit crews, to just straight up random teleporting, multiplayer is completely and utterly broken. With a supposed brand-new netcode, which showcases Codemasters "master" coding, multiplayer has been crippled before even mentioning there new matchmaking system known as "hoppers". The main problem with the new system is the player base gets spread out so much between the different game types that it takes so much longer to find the game even in the first week since release.
After having played the game for a longer time period now, I would only recommend this game to people if you are only/mainly interested in the singleplayer experience. If Multiplayer was the main attraction stay clear as if it was a sprintmode lap 1 trainwreck of a pileup.
Further updates pending upon release of further patches or DLC. 14/07/15