The first Most Wanted game is, for me, the greatest game to date. The story was solid but not intrusive, simply a list of 15 racers to beat throughout your career, each with a more appealing car than the last. In comparison, the recent Most Wanted was a HUGE disappointment, mostly due to the fact that being caught by the cops was without punishment. Bought and sold within the week.
Rivals, on the other hand, brings back the punishment of being caught by confiscating all of your ‘speed points’, the in-game currency. This appeal is somewhat lessened by the fact that cops can ‘resume the pursuit’ seemingly at random, with no cops to be seen on your map radar, let alone in sight.
An additional oddity is the fact that you can escape a pursuit by simply entering a safehouse, regardless of the number of cops on your tail. Escaping in this fashion leads to a rather unsatisfying anticlimax.
Though the above is my biggest gripe, the game itself is actually build very solidly. The online interaction is an innovative twist, and the concurrent police/racer careers provides some variety when things get a bit stale (which, unfortunately, they do). The cars sound fantastic, and though steering was initially very heavy for me, you quickly come to terms with their handling style and are soon sliding around corners with ease.
I would recommend renting first, as you'll see everything about the game that there is to see within the first two hours, excluding some of the higher level cars.
Bring back MW1!!!