I have a question about this. If you subscribe, does the extra content get added to the single player game as well? Or does it only apply to online? I am thinking about getting this, but I do not play online. I am trying to decide which is worse, not getting any expansions or having to pay 10 bucks a month for them.
I believe the developers have said that a SP patch will be released with this 1.0 content, but I seem to recall hearing it would NOT be standard practice and I'm not entirely certain they were talking about the subscription-only content with this SP patch. This is mostly because they have no way of handling local data, and as such you could simply subscribe - download - and cancel. That way, you would get all content at any given time for only one monthly payment, and would theoretically not have to pay again. I don't know if that's the only reason, but I'm pretty sure it's a big factor.
Also, in my personal opinion, the entertainment value of this kind of game increases many times over by playing it cooperatively. I know tastes vary, and that's great, but I think the gameplay focus is too narrow for a truly satisfactory experience in singleplayer. But, to each his own, and if you enjoy something like Diablo 2 in this way, I don't see why you wouldn't enjoy Hellgate.
That said, there is even less emphasis on a storyline and interesting narrative than there was in Diablo 2, so it's really about as far as you can get from the adventure part of a traditional CRPG.
There are basically 3 things to this game: Killing, Looting, and Growing. Luckily, these parts are done EXTREMELY well, especially the first two as the last part (character skills) have been the target of much critique, though I personally don't share that perception.
In my humble opinion (backed up by 26 years of passionate gaming), the game is better at the core hack and slash gameplay than any other game before it, including Diablo 2 itself.