easyform is not feature compatible with PFG as we found out recently. It doesn't have TAL expression overrides for things like the email address for example. But other than that it seems to work ok. PFG also works in plone 5.
Plomino is by far the most flexible and feature rich plone 5 form builder. The next iteration will be much simpler for non technical people but due to its features it will always be somewhat more complex than both easyform and PFG.
2 years on - I have the same question. What's the state of migration from PloneFormGen to collective.easyform? The branch mentioned above has not been merged, yet the news in PFG is that it won't move off Archetypes. Has anyone done an automated migration for this, or is it manual only?
Ps I'm back ! (courtesy of those nice guys at 4TW)