Well, Patrick, we're actually doing that project in 4.X because we don't see any reason for new development in 3.X. It's still a good system, but it's not very elegant and we don't see any future for reasonably powerful new development.
That being said, 3.X is still great for a very nice community site. It's still the best thing out there for building real DB dependent web systems, meaning it's better than at least Zope for some things (and Zope is better at others.)
I can't speak to the learning curve, but I imagine that it will be much less steep than the bootcamp presented to you. I wonder if it isn't unlike the Oracle to Postgres learning curve -- you already know one heavy DB subscribing to all the fundamental SQL and database rules, how hard will it be to learn another?
talli
