Nothing amazing but they are better than the incandescent bulbs, the like is white, which you'd expect from LEDs and they are brighter, which makes it a bit better for reversing at night.
Well, I've had 1 fitted for about a week and when parking at night I can see the difference between the two different bulbs.
I bought them from T8ups.
I got no errors but I'm not sure if the bulb warning system works on reversion lights.
any here, here's some pics.
I used the same camera settings on each image to make the comparison easier.