Only games with CCP support
I'm about 90 percent of the way through RE:R, and I think it's safe for me to say that RE4 is the superior game, although they are similar. RE:R is so obviously a game built for a handheld on hardware weaker than the Wii/Gamecube. There aren't many different types of enemies, the environments are mostly hallways and corridors, and stages get kind of predictable (proceed somewhere, fight a few enemies along the way, big fight against a horde at the end of a stage, occasional boss battle repeat).
RE4 has more open areas that require you to do more than stick your back to a wall and shoot everything til it dies. It has more varied enemies that require different strategies. It has more unique bosses. It's customization options are a matter of opinion on which you'd prefer over Revelations: instead of finding parts, you pick up money from enemies or find it lying around to buy upgrades from a salesmen. The only thing I think that Revelations does that is superior is the inventory system, and that is also up to one's opinions, because you can technically carry more than three guns.
But yeah, a lot of RE4's praise comes from the fact that it pretty much turned the survival horror genre on its head at the time.