Yet, Legend AI is definitely tuned for manual gearbox. You can easily beat them by up to 5 seconds per lap, depending on the track, if you're using the automatic gearbox.
I just picked the game up even though I don't watch F1 races and haven't played previous F1 games. I'm really enjoying it so far. I think I'm on the Valencia race in my first season. It's definitely a challenge to learn how to drive these cars and getting to know the tracks. For the first season I will leave on driving line, the next I will turn it off. My goal is to by season 5 be running full length weekends with no assists and manual gear box. We'll see. So yeah, I recommend it for anyone on the fence about it. I also plan to start watching F1 races this upcomming season now that ordered Direct TV.
TBH I watch F1 I'm not the biggest fan but I do enjoy watching it when I get the chance. I got this game when it came out played it for maybe a month and went straight back to GT5, It just sits collecting dust now.
I don't know if the game has been updated in anyway since it's release to improve it but for me personally it wasn't up to standard.