I got a 3-speed (Trek Belleville) a month ago and commute 14 miles a day on it. I LOVE this bike.
Trek Belleville side view by
CarFreePhilly
As someone who commuted on a SS for over a year, it's great being able to shift down at a stop light so starting up again is easier. It's also nice to have a fall-back gear when my legs are just really tired. I've yet to use 1st gear--too much spinning. My commute is through the city without any huge hills, and I don't worry too much about going super fast. That said, I've enjoyed passing my fair share of hipsters on fixies and guys with kitted out hybrids

I wrote a review of it
here.
I'm sure one downside is fixing a flat with an IGH. I haven't had to do it yet, so I can't speak to that.
I would have gotten the Nirve Wilshire, but they don't make frames small enough in the men's size, and I didn't want a traditional stepover frame.
Flammenwurfer, that's a gorgeous bike!