Great thread!
I'm a Logic user considering an alternative. One of the main reasons is Logic's quirks with external sequencers, but it sounds like S1 might not be straight forward either.
I'm 95% MIDI (mostly virtual instruments with some MPC Live sequences mixed in) with the occasional bass or guitar recording. I like Logic's MIDI, but S1 has some cheat codes Logic doesn't. And S1's mixer seems to have more flexibility.
The hunt for MY perfect DAW to create & mix in continues. S1 is the only one I'm looking at currently. It's either S1 or stick with Logic.