That's good to hear. May not be as good as Halo: CE, but at least I know it's better than Halo 2 & 3.
I find it funny that people say Halo 3's campaign was poor.
Sure it may not have been groundbreaking and original like Halo 1 or attempted to be epic like Halo 2, but it is easily the most focused and fast paced Halo campaign (till ODST which kinda added stealth elements and wasn't as action oriented)
I don't think there is a single point in Halo 3 when I sad "damn, I really hate playing this part"... Halo 1 had that long repetitive second half which was pretty much the same coridor fighting with flood over and over. And Halo 2 was...like you said a huge unfocused mess.
I never said it was bad, it just wasn't as epic or as engaging as it could have been. The campaign lacked any thrilling set-pieces that had me at awe, and the battles didn't convey Earth's desperate struggle against their final battle against the Covenant. Also, the Brutes replaced the Elites. The Brutes are rather simplistic in their offensive tactics, and almost had no defensive strategies what so ever. The enviroments weren't big enough to provide the sandbox combat approach the series was built on. They were pretty easy enemies to fight, they don't hold a candle to the Elites. I will say that the Scarab battles were pretty epic, and the vehicle sections were awesome as always.
Every mission in Halo: Combat Evolved were varied and offered exciting set-pieces. It also had open fields that allowed multiple approaches to the combat. The only complaint I have with CE, is that the interior levels are repetitive and The Libary. Other than that, Combat Evolved was an excellent game. It still holds up against today's scripted military shooters and archaic old-school shooters of the past, which everyone seems to love these days.