Did a study on that but I won't go for any, all lousy, no best bang for buck, including CPF Life (if I have a choice).
Problem with these life annuity schemes are that they give very good illustrations, non-guaranteed 4.5% etc, but in reality you won't get even close to half of those even 30 years there after.
For CPF Life, the problem is with the low payout and bequests, coupled with yearly adjustment that seem to be getting lower and lower (in the name of "increasing life-span" - I don't know how that can happen when their calculation for CPF Life payout and bequest already estimated that all of you will live till at least 93 years old, while 50% of men would be dead by 80 years old)!