I haven't read most of the thread and don't know if you already have the 18. My wife uses the 27 on her XE1. Comparable lenses I use are the 18 and 35 on an XT1.
27 is a nice in between FL. I consider it a good compact walk about lens.
What it not so good at is indoors where it's a bit long. Close-ups. Squeezing the most out of low light when you simply need more shutter speed.
My combination of the 18 and 35 gives me everything above other than small, and better than the 27. On the XE1 the 18 will focus quicker and not hunt in low light (the 27 will hunt, perhaps not as bad as the 35 but it's not unusual for it to fail to find focus).
She paid $249 for the 27. Both of us would rather spend more for the 18. Since the 50's I've primarily shot FF 24/35/50. The 18 (FF 28) was new for me but I find I like it a lot. For casual use and good low light performance it's a great little lens.