With slightly lower numbers than the ones you give and at similar age, DH elected to take the lump sum.
Under DH's pension he could have chosen a 100% survival option which is what he would have done. But PBGC would have only been obligated to a 50% survival option in the event of default.
Also, PBGC's maximum amount that it would pay was less than DH's pension.
Although the pension was very well-funded you just never know what will happen in 10, 20, 30 years. So he took the 7 figure lump sum which he rolled into an IRA. That was a couple of years ago and so far we aren't sorry at all for the choice.
Our reasoning was that if we wanted an annuity if he took the lump sum we could always buy an annuity. However, if he took the annuity (i.e. the pension) he couldn't trade that in for a lump sum later on. Therefore, the lump sum gave us more flexibility.