At first I picked destroy, because Anderson did it and I could only follow about half of what was going on with the awesome scenery in the background. The only reason why I doubted the decision was because when he said "You will destroy us, and end this cycle.." I thought he meant everything in the current cycle would die. FATALITY. FINISH THEM.
I decided to focus 100% on conversation the next time around, and synergy sounded the coolest, combining synthetics with organics, making super reaction time and fast thinking people walking around, aging far less over time etc. Well, when I saw the ending for that one, I'm like well shit, circuit board synthetic-organic plants (fucking weird), Shepard doesn't survive... fuck that.. I was still right the first time.
And then control was just dumb because Shepard fries himself, then flies off as the Reapers and bores himself to death sitting in dark space. Hell, I'd come back and visit from time to time to scare the shit out of everyone because I could. Then possibly get indoctrinated. Then end up doing the same shit the Reapers were doing, except in a shade of blue instead of red. I could kill my massive army after I make a Big Super Giant Fucking Flagship, BSGFF, naming it like I'm lazy, but meh.