I voted autonomy off for selected Sim. But it's really a mix of "autonomy on" and "autonomy off for selected sim". With relationships I'll often times make the initial introductions but then let the conversation and relationship gains or losses go where they may. I guess in a way I let my sims tell me who they are interested in. When a sim comes over for a visit I'll usually turn on full autonomy and just see what unfolds .... after locking the door to the computer room for everyone :p
If it's a night before needing to get up for work I'll usually go "autonomy off for selected sim" so I can make sure all their needs are met. Or if they've been stuck in their career and not getting promotions because certain things need to be done then I'll usually take over.
I usually have an idea of what my sims are going to be like before I even start, so I try to play them like that. But I turn on full autonomy enough to often times be surprised that they have evolved into a different type of sim than I initially expected.
Edited to add: Even though it's not nearly as bad as previous sim games, I never let my beginning sims cook anything until they've leveled up cooking a few times. All my new sims either order pizza or make salads so they dont burn the house down or catch on fire. Coming back after a long break, so assuming there is still no fire department or plans on implementing one.