Drost at 2Old2Play reviews Halo 3:

In Halo 3, you're going to war. In a very real sense, Bioshock and Halo 3 are different genres. Sure, they're both shooters, both FPS, which technically makes it seem as though they're the same, but ... no.

Which you like better may come down to a matter of preference, but make no mistake, Halo 3 is a damn good game. It's all the good parts of Halo with the visuals that were promised in Halo 2 if not quite delivered. A little repetition on a couple of levels, but there are some battles you'll fight in this game that are larger I've ever participated in any game.

Bungie kept saying there were huge encounters. They weren't kidding.

His final verdict: the "most fun I've had playing a videogame."

On an interesting sidenote, he had this to say about graphics:

Seems to me comparing and contrasting the graphics between games is not unlike a pixilated Johnson-measuring contest, and it's a no-win anyway. If you say, "but Halo's visual style is different than that of Gears or Bioshock," it sounds like you're making an excuse.

I think we're finally starting to get into the era of game design where we need to start talking about art direction. We're now comparing cinematography, not just level of detail. There are bigger things to consider.

If you ask me, we're about ten years late in talking about that; there were clear differences to be seen even back then, but the gaming press was starting to ramp up to judging everything in terms of maximum resolution and frames per second.

Look at Doom and Marathon. Marathon contains locations that feel real; a massive colony starship and an eerie alien scout craft.

Doom contains a Mars base inexplicably strewn with burning, exploding garbage cans, and a lot of half-baked Satanic imagery.