Any experience with ISL29125 RGB sensor?

Using Sparkfun's turorial I have their ISL29125 breakout hooked up and am getting lots of grey-blues rather than decent colours. (Yes, I have the 3.3/5V thing taken care of with a level shifter; device initialises successfully.)

I'm sending the r,g and b to python to be reconstituted as a colour but everythings coming out kind of dull.

"Servo orange"comes out as a yucky grey/blue/green for example. Bright light goes white, cover it up and it goes black, but no real rainbow moments in between.

In its defence it does say it's an "rgb light sensor" not a "colour sensor" as such, although the supplied code does split the 3 elements of r, g and b out.

I was hoping to get results like this guy got, although that's a different sensor.

Anyone used this sensor (in the Sparkfun breakout or not)? If so, with what success? Did you use the tutorial code or what?