I previously bought the 200 credits package for $40 or something, and that was going to last me a lifetime - didn't need it besides renaming players at a buck a pop, but wanted to say thanks for the game by paying up.
I completely understand that jdb needs money to make it worth his time to try to develop the game. However, I agree with people in the main discussion that he should have released ANY kind of improvement before setting up the subscription tiers - make a good faith showing that he is still actually trying to make the game better. With so many teams getting dropped right away (Wizards, Bangles, Dreigau), I'm sure most people are going with the one team free model, or at most the cheapest ad free tier (which I did with existing credits). He might get a small windfall from this right now, but I doubt a lot of people are going to want to make a big investment.
Like gopher said, if you enjoy the game and can afford to pay something you should, but I'd hold off on a top tier unless you absolutely love having 10-12 teams - I prefer putting lots of time and attention into only one or two, but that's just me.