I finally have my Diatone Blade 150 flying! It is a lot of fun! Right now, I'd say I like it as well as my 250mm sized quads. I think it has a different purpose. It is slower (but not by much) and I think people in general are less intimidated because of its small-sized "cuteness". Also, due to its smaller mass, it has been less likely to break during crashes - except on concrete! It has survived several tumbles through trees.
At this point in time, it isn't much cheaper to build than the larger ones though, but there have been rumors of 1106 motors being released soon which would be ideal for a quad of this size. Hopefully, they'll be reasonably priced.
This is a pretty long video but includes building tips, parts list, tuning tips for OpenPilot, and flying footage from two different locations.
You can build your own identically to the one in this video using these parts:
Diatone Blade 150 Glass Fiber frame with built-in PDB:
DYS 1306 3100kv Motors:
DYS BL20A ESCs:
Mini CC3D Flight Board:
LED Decoration Board (solders to the underside):
D4R-II Receiver:
Taranis XD9 Plus Transmitter:
FBVS-01 Battery Sensor for Telemetry:
Camera & Video Transmitter: