I like to come out as close as possible to track-for-track. I will use stems (often 'keys' or 'guitars', almost always 'FX') if my track count exceeds available outputs.
I know this is not very 'advanced' in the sense of what a DAW can do WRT making recalls easier, etc, but I made the decision at a certain point that I would make my investment in analogue equipment, which holds its value both financially and in terms of utility, rather than plugins, which are constantly being updated and must be kept current with the DAW.
So in reality, I think this is a financial decision. I run my own (small) place, so I'm in a different situation than, for example, William, who (I'm assuming) works in a variety of places and must be able to take his tools with him when he goes. Further, I like to have analogue available when tracking, so why not expand my analogue options and then use them during mixing?
I think what I'm trying to say is that my decision has been made not on the basis of how the summing sounds, but on all the other things that my chosen workflow entails.