-Open world style gameplay (with day\night cycle)
-Cops and racers
-Cars can be repaired at garages throughout the map
-EasyDrive system which gives you a path to the nearest events (races, time trials, etc etc), repair shops, hideouts (Rivals), etc etc
-You earn SP required to unlock cars
-Different game engines
-RIVALS HAS NO FRIGGIN PAUSE (AAAAARG)
-You can actually play as cops. Cops arguably have it easier as you'e not being chased 90% of the time and can play at your leisure.
-Rivals has a garage\hideout area where you're "safe." You personalize your cars here and choose your next objectives. You're not driving around when you're here. Its just a menu.
-Gameplay in the actual world is played in sessions. Each session you have a list of objectives to complete. You build up SP (to buy stuff with) as you go. You can only save SP by returning to a hideout. If your car health reaches 0 or you're busted by cops, you lose your SP for that session.
-You don't switch cars in the game world, nor do you find new ones in the game world. You switch via the garage\hideout. You also upgrade there too.
-Rivals has a progression system based on rank. You need a certain rank to unlock certain cars, as well as enough SP to do so. The game objectives get harder as you go up in rank.
-You have "pursuit tech" in this game. Cops and Racers have 2 slots for these. You choose 1 pursuit tech for each slot. These can be offensive weapons, defensive weapons, or simply turbo (super nitrous). For example, "shockwave" sends out a blast in all directions that pushes other people away. If timed well you can shove a car into oncoming traffic... or just slam them into a wall. Great to use if a car is trying to pass you on the side. You have a limited use for each and there is a cooldown. You can refill them at a garage
-Rivals actually has rain
-Rivals has helicopters on the cops team that will follow you, shine spotlights on you, and drop spike strips on the map
It's hard to really list differences in a bullet point list because you kinda have to explain the gameplay system in Rivals in detail to really get at what makes them difference. The biggest difference to me is the fact that you're always in the game world in Most Wanted and you can drive at your leisure. Cops won't chase you unless you do something that warrants being chased. In Rivals, you jump into the world in sessions and it can get hectic pretty fast as a racer. Cops will chase you for no reason other than the fact that you're a racer and all racers have a default wanted level that only increases. The longer you play in Rivals, the harder it gets as you will slowly get a higher wanted level and more and more cops will be chasing you. Sometimes it feels like you can never get away and you HAVE to return to a hideout, otherwise you'll be busted and lose your SP. The game encourages you to stop playing and what's worse is that you can't even pause while playing.
All in all, I think Rivals has the potential to be a much more fun game. Sometimes it's really satisfying to jump into an online session as a cop and just cause havok for other people (actual people show up on your map with their username). It's also a ton more frustrating at the same time due to some of the game design choices they made...
Edited by jim2point0 - 11/27/13 at 6:55am