Jonwrote a review of Race Face Narrow Wide Chainring on June 10, 2016
Familiarity: I've put it through the wringer
I got doored on my commuter bike a few months ago which resulted in a few scrapes and bruises along with a bent chainring. I wasn't a huge fan of the stock gearing, so I decided to swap everything out. I'm using a 38t with a 9spd 11-28 cassette. I would have preferred a larger ring, but those don't seem to be available in a 104bcd and I didn't feel like spending a ton of money on a new bottom bracket or crank. I'm a big fan of the 1x commuter, and will likely go with a real 11spd system if I ever trade in my Sirrus Sport.
This is a pretty good site for seeing how your gearing will change: http://www.gear-calculator.com/