I commute pretty much daily, not sure the bike I usually use for commuting (a hybrid) is marketed as a 'commuter bike' though.
However I have been commuting for a while on dutch bike with a step through frame - that should count, even though it had derailleurs as opposed to SS or IGH.
Things I liked about it:
- Full fenders and chainguard do a good job of keeping clothing tidy
- rolled very nicely
- frame lock comes in handy when popping into a store for a minute
Things I hated about it:
- I don't like the looks of full fenders and chainguard.
- it was rather heavy at around 38 lbs. It was felt un uphills and when accelerating.
- didn't like the upright sitting position and backswept bars. Not so much because of increased air drag, but the backswept bars interefered with my knees when navigating tight turns, and the sitting position put most of my weight over the rear wheel, which made steering in snow tricky.
- the combination of head angle and rake made the steering twitchy.
I never once used the rack during the ~5 month period I used it. I'm used to carrying a backpack, since my usual ride don't have a rack.