Overstress,
As you say, I'll also retire at 60 with a larger pension than if I'd retired at 55 on the old pension option.
Con:
i) I'll have to pay more to do this ie. larger monthly contributions and for an additional 5 years.
Pro:
i) The fund should be stable compared to the present situation.
ii) I can remain at BA until I retire at 60 instead of going to work for one of the low-cost airlines.
I'll be voting 'yes'.