Originally Posted by
efamous
If price, scheduling, etc. are broadly comparable, then I'd say go for Iberia. Assuming you're on a cheap Economy ticket, you'll get slightly more base miles on Iberia (30% vs. 25% on BA). Also, I think Iberia still has bonuses for GLD/PLT/EXP while BA doesn't.
Anecdotally, IB is also more generous with op-ups for other OW elites on crowded flights, but obviously you can't count on that happening.

Interesting. I didn't pick up on the bonus mileage issue. That is very important to me.
I will be flying on the Government's dime and I think they will be paying for a refundable Y ticket, so hopefully either way I'll get full miles.
A confounder is I will not be coming straight back to FRA, but rather DFW for a week. I'm thinking JNB-MAD-DFW-FRA might be a little more tolerable than JNB-LHR-DFW-FRA.
I think I need to go over to the BA section and check out fare bases and upgrades to Premium Ecomomy.
(As you can tell I am chasing my tail on this....)