My new ultra-gauge stops reading a number of sensors once I start
the engine. Even with the latest FW with a new mod for the 6.0
they are still having issues reported. I've worked with their support to
try to resolve my issue, but they are gettting other reports as well
from F250/F350 6.0 owners.

I'm going to return the unit for a refund, but was wondering if
anyone has had any problems with other electronic ODBII readers in
the '05 6.0 (Ex, F250, F350) models.

No need to go buy an Insight CTS if it'll have issues ready the
sensors too.