I'm a relatively new M2 owner (about 3 weeks now) but I had an inexpensive "starter" printer (Makibox) for a few months before leaping to the M2. While wrestling with that first printer, I experimented with all of the freely available slicers I could get my hands on, and was amazed when I first used Cura. The gcode and toolpaths it generates are so much more intelligent than those that come out of Slic3r - far fewer retractions, much longer, continuous toolpath segments, etc. Almost exactly like the differences you folks are explaining between what Slic3r puts out and what S3D generates. I haven't tried S3D yet but am getting pretty close to pulling the trigger for the combination of what sounds like very intelligent slicing, integrated machine control and greater alignment with the M2 user community. But for anyone who isn't ready to drop $140 and is unhappy with what Slic3r is doing for them, I highly recommend trying out Cura. It made a massive difference in my success with the Makibox. I will say that Cura's support generation seems no better to me than Slic3r's, so I'm looking forward to this (hopeful) improvement with S3D as well. Thanks all for sharing your experiences.
Now back to the cetaceans.
P.S. To be very clear, I wholeheartedly commend those behind Slic3r for all of the work that has clearly gone into it. I find its settings pretty straightforward to manipulate and it can generate reasonable gcode. The integration with Repetier-Host is great. I hope that it continues to be iterated and improved and am happy to have donated a few dollars to support development.
Show off your prints!!!