An importer is being made, but isn’t done yet. You can follow the progress of it here, https://bbpress.trac.wordpress.org/ticket/1547.
Which one is better depends on your needs. I plan on switching my phpBB forum to bbPress because I think it better suites my needs.
The bbpress plugin will work with Akismet so spam shouldn’t be a problem.
Thank you Andre. I really appreciate your time.
So until then, forgive my ignorance, what might be the best way to import the old info manually from the old database?
I wish I had a good answer for you, but I don’t know.
I have written a converter for phpBB (prob an older version) to bbpress (the native Word Press version, Version 2.0-beta-3) for a client. Imports everything but the private messages at the moment. phpBB usernames had to be massaged to have spaces and punctuation removed.
This would not be free, but inexpensive, shareware prices. But a few beta testers to see if it might be generally useful would be nice. Contact me if interested.