I've continued to follow this thread, and also re-read some of the earlier responses. In my impression, the App Store is still an unknown quantity. I have it, have tried it, and have even bought a few things from it. Then I removed it from my dock, and only check on it from time to time when I'm procrastinating. From my perspective as a long-time Mac user, fairly savvy computer geek, and generally a fan of things that Apple does, it's too early to tell if it will have the same "gold rush" impact on the Mac as it has had on iOS. I would certainly be hedging my bets on that call.
So, I just thought I'd put this out there: Please don't hesitate to change directions if you need to. If the App Store isn't driving the customers to you and you need to go back on the "free upgrades" policy, I will be one of the first in line with money in hand. But since you won't take my money anymore (

) the best I can do is offer some encouragement to get you through the gruelling feature-planning meetings, or week-long bug-hunts.
I think Mellel is the finest word processor out there, and I'm fully committed to it. I think a lot of your users are, since Mellel isn't the type of software that is handed down by departmental decree or forced by IT policy -- your users actively search it out and put their time and energy into learning it. You have people that are not just
using your software, but
investing in it -- getting their styles just so, or tweaking their auto-titles setups, or making their own set of document templates. I think that shows that you're not just making good software, you're making a professional tool (which is one of the highest compliments I think I can give -- it's the difference between the $10 kitchen knife, and the $1000 kitchen knife).
Please (and I mean this quite literally), keep up the good work.