It's been well worth it to me. The replay value has been very high in both campaign and versus, though some clearly do not feel that way. I'll enjoy having the other versus campaigns for sure, plus looking forward to community maps.
The down sides for me are twofold. First, I am unsatisfied with the lobby/matchmaking system. This has been discussed a lot already. Secondly, pretty much the same thing you can say for most online games where you try and enjoy public servers, it's impossible to avoid encounters with trolls/griefers/punks. As I said, I realize that this is just an aspect of public servers in any online game, but an improved lobby system would help.
I'll repeat what I said in another thread. A versus campaign is a pretty decent investment of time, so it would be good to have a more discriminating choice of what games you are joining, instead of immediately being whisked away into a server before finding out that you are the only one on your squad that is on voice chat, and that the other squad is a clan, etc. I don't actually expect big changes in the system, just pointing out a valid issue.