Actually they are playing nice. I asked over there. The first 12 months you are a full registrant.
a) After 12 months, if you still want to upgrade, you will pay $119 and be able to download for 12 more months which ever version is current.
b) App never loses functionality. What you installed will work forever. However, keep your downloaded installer - if your upgrade license expires,you won't be able to download from our site anymore as we don't keep old versions.
c) If you purchase now for just 10% of the standard price, we still give you standard 12 months of free upgrades, starting with the purchase date. All further renewals afterwards go with standard pricing, of course.
If it helps with one database conversion, at $29 you are ahead of the game.
On the other hand, a lot of what you might want to do might have database importers to your target .. in that case this software might help with automating, which would not be a factor for a one-time converter, one real question is which does a better job on the conversion. There are always issues with data types and such.