But, if you have to use PGM, I don't like GPS based guidance of any kind. It may be convenient against low-tech threats, but a real enemy will be capable of corrupting GPS signals, or in an all-out war actually taking out the satellites. Laser guidance done right requires an undetected ground team, but even if you have to use an aircraft to spot your bombs, it is far more secure than gps delivery. But if GPS is up, you can't beat the stand-off range, and GPS combined with B-52/B-1/B-2 platforms is a nightmare for an enemy unable to defend against them.