Does the series favor a certain console? In other words, better on 360 or PS3?
I'm a bit of an OCD nut when it comes to this stuff, and I have this dumb propensity to buy Criterion games on both the 360 and PS3 this gen. So here is what I can tell you.
Criterion is certainly know for platform parity, so you're not going to get a bad product on any platform, but if you're an OCD nitpicker like me, you'll notice some things.
Burnout Paradise - There are a few more hitches when playing this game on the 360 than there are on the PS3. Both versions run at 60fps and run very well, but in super high action moments, occasionally both versions can wheeze for just a moment, and these moments are just a little more common in the 360 version.
Need for Speed: Hot Pursuit - Once again, both versions are very similar. Both run at 30fps at all times. When you load up the world map at the beginning of the game, it stutters while doing it's fancy transition on the 360. It executes this transition perfectly smooth on the PS3. Also, when playing the game over optical audio cable on the 360, you'll sometimes have the sound cut out for a split second at very intense moments. Just for a split second, that's all. This does not happen on the PS3 version. Lastly, each race begins with a transition from a cut scene to actual gameplay, and these transitions are always smoothly handled on the PS3. On the 360 this is not always the case. Sometimes there is just a momentary 'blip' when the moment actual gameplay begins.
Burnout Crash - This game has one big notable difference in the two versions. Aliasing, otherwise known as "jaggies". They're kinda ridiculous on the 360 version, and they're perfectly acceptable on the PS3 version. Why it turned out this way I have no idea, because this game clearly isn't pushing the hardware for either console, but that's how it turned out. The 360 version also has a few momentary hitches in the menu animations.
Regarding Most Wanted, so far we've had journalists who played both versions suggest the PS3 version looks better, with sharper textures and colors, and another writer mentioned the 360 version having some framerate hitches. It's possible these things could be ironed out for the final release, but if I had to bet on it, based on the prior history I just laid out, the PS3 version will probably have a minor edges in a few areas.
As I said though, these are OCD like differences. More than likely Most Wanted is going to provide an extremely similar experience on both consoles for most people who play it.