Leaph I don't really think you know what you are talking about when it comes to gameplay. Halo Reach isn't like Halo 3 much at all. It's more like it's in between Halo 2 and 3 with the slight cross of some Modern warfare in it.
Also they aren't similar in terms of content, such as forge world, load outs, and the physics have ever so slightly changed.
Yeah, just started playing the campaign and seriously? it's SOOOO boring, when does something really fuckin crazy happen? Like versing two scarabs at once, with a shitload of covenant around.
Also I'm not liking the firefight aspect just to advance in some places, that shit is filler, like if L4D decided to give you a scavenge objective in the middle of the capmaign just to progress, not at the end, but in the middle of it.