Last addition about my opinion on the game since I just completed the story mode
Well... in short... it's short
Today is the official release date and I already completed it

GTA with its side missions is way better from that point of view. Driv3r is very straight forward, no side mission at all, ence short...
Only two missions are a bit of a challenge to tell the truth

one of them beeing the last one obviously were you have to fight tons of enemies (wich cause also many slowing down, frame rate-wise...).. with some hardcore play you can complete it in a day, max two
But I don't care, I would rate it a good 8/10 on my personal scale because for sure I will still play a lot in "free drive" mode

to unlock the secret cars and just to discover all the nice places