Destroy them. I don't like the ending I got, mainly because I have no clue what the fuck is going on. I don't understand how some kid that's human at the beginning of the game shows up at the end as some kind of holographic interface or....WHATEVER he is, apparantly created, or controls the Reapers, I don't remember, the ending was such a mindfuck I've forgotten parts of it, then gives you a choice of destroying the Reapers, controlling them or the synthesis ending, and no matter which one you choose (I watched the others on Youtube), the ending basically looks the same no matter what with the Normandy crashing on an island without FTL travel, basically leaving them there to die stranded. Maybe I'd like it if I could make sense of it but it's flat out ridiculous as far as I can see.