Let's see. Resistance's campaign was pretty fun throughout, and really showcased what the PS3 could do. Near the end, there were some levels that required you to do stupid things to beat them. I hate having to use a strategy guide on a game just because they make a level that gives no explanation of how to beat it (Meaning, die ten times, go look at a strategy guide, die 5 more times before you finally beat the level).

As far as the Resistance online play, for the length of time I played it (Many months on end), it was excellent. The learning curve wasn't too high, you're only problem is that Insomniac designed spawn points in a 40 player level that spawn you standing in between ten people shooting each other. It's so much fun dying because of where they place you. The spawn points were too predictable after a while.

With Halo 3, the campaign is decent. I did not like it as much as Resistance (Although I did not play Halo 1 and 2, so I learned the story as I went along). There didn't seem to be as much as a story in Halo 3, and it was just about shooting, driving around a little bit, shoot some more, get killed a lot. I didn't enjoy it as much as I wanted too. Also, a late level in Halo 3 is a total rip-off of a level in Resistance. When you get to it in both games, it will be clear to you which one I'm talking about.

For Halo 3 online, at first it was very similar to Resistance in my mind. Then I noticed that the levels seemed much smaller than most of the Resistance online maps. The level up system, of pitting you against players of your skill and slowly moving you into ranked matches with higher skilled players, actually works, believe it or not.

I found quickly that people cheat all the same in Halo 3. I've seen laggers. There are a few weapons that are basically one hit kills. People camp at them, or camp at popular "Elevators" holding the weapons. Those people obviously never win a match, they are just there to annoy you. After a few days of playing online, I feel like I've done it all. There isn't nearly as much fun to be had as in Resistance online.

Verdict: Resistance online will keep you happy for many more months than Halo 3 will. I don't think I will play it much more online. For campaigns, they are pretty closely matched, but Resistance wins that again. I will never play through the campaigns again on either game, because it's not worth it on either system. I've seen it all, no point in playing it on a harder level and dying more just to say that I did.

Hope that helps with your decision.