It's going to cost the same amount for the season pass as it will for all of them separately, so it's up to you. If you're sure you're getting the next three, you may as well buy the pass out of convenience of having them all paid for already. If you're not sure if you're going to buy them all, do them separately, obviously.
Are you suggesting that moon should get off his ass and write some stories? He's like the Stephen King of gamefaqs. - Sorbz