Raiding what? There are a lot of things in this game that are considered raiding.

Raiding 24 mans? Its a casual spectacle of running with a small army through a large dungeon, with some neat bosses and mechanics. The incentive is the catch up patch gear, and the spectacle.

Raiding 8 man NM? Same iLv gear as crafted gear, and i380 is a good first step to doing 8 man savage raids.

Raiding 8 man savage? iLv cap gear early in the 6 month gear tier, and bragging rights, really.