Which one is better for a web site, .net or .com?

I own a website and I have on .com articles written by people and on .net is the forum, also the forum is vbulletin with cms and has on main page articles with all kind of promotions. Now my question is, it is OK to have forum on .net ? will this be a problem for Google ? Do you think I can rank higher if that was on .com domain, with same amount of links pointing to domain ?

People tend to hit the .com at the end, but as you own both domains will not be a problem just link from .com to .net with a small banner or some links so people will know the forum is there. I think that is the only main difference.