I have a colleague who's great when it comes to talking but is actually not very good in the work he does. This guy has the support of the management and is ready to do whatever it takes to make his team and himself more successful even if this means stepping over other people in the company. We don't work for the same market but we need to exchange team members and he wants the best people.
I found out that he was playing dirty, talking with the team members privately and trying to convince them to join his team. I'm OK with them going in another team, so long as this is their will, but convincing them behind my back I consider unethical.
Should I start gathering info about his actual achievements and have my homework done and then go to the management (this actually means office war) or should I talk to the guy and try to smooth the situation. Or should I do something else?