Two completely different items. One is life insurance that pays a set cash lump sum upon the retiree's death (VGLI) and the other pays a percent of the retiree's retirement to the surviving spouse (SBP). It just really depends on what you want. Maybe you want both.
Question one - who is dependent on your retirement/VA comp and for how long will they depend on it? Don't overlook a commercial term life policy option as well. It is hard to say what would be the best option without a deep dive into a lot of specifics.