With the functionality in the "free" editions, and the ability to use them in production, there should be no question whether someone ought to use a lower functionality open source database or Informix. Informix is the only logical choice.
I also like the fact that Informix is backing away from the a la carte pricing for various features in the For-Purchase editions. Yes, there are still a couple of for-charge add-ons but we're getting back to "you buy Informix and you get it all" way of doing business.
Anyway, I've updated my developerWorks article with the new packaging information. There is a typo or two that needs to be corrected but we'll get that worked out in day or two. If you haven't taken the time to look at the new packages, the article would be a great place to start.