There was a rather ugly little row on the HBO forum prompted by some trash-talking against Halo and in favor of the newly released Timesplitters 2 for the Xbox. However, one good thing did come out of it: Scalrag posted a rather even-handed comparison of the two games, and what he likes/dislikes about each:

The single-player story is a joke. The evil Timesplitters hide the powerful Time Crystals in various points throughout history...and then leave them there. They don't bother hanging around to make sure the crystals aren't found, they just assume that they'll be safe and move on. Good villains are hard to come by, but these guys are borderline incompetent. [...] TS2 was designed to be a multiplayer experience, with a single-player game tacked on for additional interest. Halo works the other way around. Both games are very good at what they do best.

Don't bother with the rest of the thread, but take a look at that post if you like Halo and think you might want Timesplitters 2.