As far as SLI on the Swift goes - I used it for few months with my 780Ti's and the only game I encountered microstutter with was Metro Last Light, but was apparently down to a bug with Physx. It worked perfectly for the most part and then I loaded up a save 1 time and although the fps was consitently high +100fps at all times, it genuinely felt like 30fps. Changing Physx to cpu fixed it.
Other than that, I had zero complaints regarding microstutter or any other issues. A shame that Gsync, DSR and SLI cannot all be used in conjunction (Nvidia claim they are working on it). Only reason I changed to a single card was a) I felt 3gb vram wasn't sufficient going forward and b) I am a sucker for shiny new things.
I would have no hesitation about going SLI again, but a single TX has thus far proven to be sufficient for driving the Swift.