IBM just released version 4.0 of their open source JDBC (TYPE IV) driver for DB2/400. I've been using JTOpen since CFMX was in beta, and have been generally happy with the results (sans a few bugs). This release boasts dozens of fixes and improvements. I plan to install and test the new driver next week to see how it performs.

If you connect to DB2/400 from CF MX, I highly recommend you check out JTOpen. You can download the latest build here:

http://www-124.ibm.com/developerworks/downloads/index.php?group_id=29