It's interesting that Criterion chose to alter game settings depending on race type this time around. Collision detection is increased in Crash mode so even a glancing blow against a roadside barrier triggers a crash. The traditional methods of gaining boost from earlier Burnouts - such as near misses, drift and oncoming traffic - are devalued in race modes with rivals in favor of takedowns. Meanwhile, preview lap/burning lap/time attack race modes restore the original methods of gaining boost to something more like their previous level of value, though only because there are no rivals in these race modes.
As for rubberband AI, I never thought it was particularly apparent in the first two games and I certainly don't think you can complain about it by the time you get to around the 40% mark in this game. At about 50%, the game is punishing me piteously for any mistake I make and not giving any sort of ground just to give me the false sense of comfort that I'm still in the race. Which I like, and is reminiscent of the original Burnout, while the first 30-40% of the game gives you the accessibility of the second game.
If I were to complain about anything, it'd be about there being too little scenery to go around for all the different events on offer and likewise too little distinction between cars in any given series for the number you eventually unlock. I'm disappointed, for example, that the "Dominator" version of each car series uses exactly the same paint job. Also, the the much more information rich presentation and UI of this outing seem to be the source of additional, unelegant loading interruptions that somewhat hamper it for consideration as a quick, pick up and play title. Esp. noticeable for the Crash mode where the length of an individual session is very short, compared to any other race mode.