I have regular SE4. I did not upgrade to Gold because (I am told) it doesn't fix any of the problems I really care about. And drones are useless apparently. I will definitely upgrade to SE5 when it comes out, or go to Gold if I run out of 1.49 opponents..
The situation I keep encountering is my ships blowing sub-100M pop planets out of the water, and I had thought that they were unloading all their ordnance into it.. possibly it could be that the large napalm bombs 3 are taking out too much pop in one shot? Is there a way of relating damage points to population loss so I can work it out?