I'm not sure what the best answer is, (though I'm obviously leaning
towards giving type99 priority over txt records.)
I fully agree with this. Receivers should not be bothered with
differences between the two. If a sender chooses to publish different
TXT and SPF records, that's his problem.
However, the current situation where permerror is required if you query
for both records at the same time seems problematic.
Then don't query for both at the same time. I fail to understand why
receivers would want do that anyway. If you have either one of these,
there is no need for the other one, other than for compliance testing. I
refuse to burn CPU cycles and bandwidth to do that. We can't
realistically ask that receivers do that in a production environment.
Arjen