I'm going to preface this by saying I haven't played the online portion yet.
Having said that, with the way Sega's going about "updating" content, I don't really have much incentive to check out the network mode any time soon. While I can't really say I'm totally surprised at the way Sega's going about it because of the PS2's inability to update content, I was somewhat troubled to learn that out of the box the network mode had less content than the offline mode. Seriously, if you're paying $10 a month for something, it should at the very least offer more to do than the basic offline mode.
Even more concerning to me is the fact apparently quite a few players run the same mission over and over again even when new content on the disk is unlocked for network mode. Personally, I just don't see the fun in running the same old tired mission
De Ragan C
3000 times because no one wants to step up to other available content.
I'll probably jump in once more of the story missions are available so I can see where the story continues from offline mode (quite an evil thing to do, I might add), but for right now it doesn't seem to be worth it to me if you can see all there is to see within your first month of playing.