September 2020 update
Tail lights - tungsten on the left and LED on the right. LED perhaps fractionally less bright, also more orangey, probably due to the white light from the LEDs through the red lens compared to the yellowish from tungsten.
Stop lights - the LEDs are noticeably less bright, which means a reduced step-change from tail to stop making them easier to miss unless a following driver is looking in the general direction of the back of your car. This seems to be a common problem with light units on modern cars with an emphasis on styling over function.
Again tungsten on the left and LED on the right. Tungsten no great shakes in bright sunlight, but unless you noticed the LED coming on you wouldn't see it at all, the indicator reflector is brighter, and that's not even on!
Stop and tail, LED noticeably less bright from directly behind, but also less radial output as can be seen from the significantly reduced reflection from below the lights. Ok no-one is going to be below the lights (although that reflection will be visible to following drivers from wet roads), but the same reduction will be at the sides, and with the tail lights as well as the stop lights.
By comparison tungsten both sides has equal brightness and reflection, showing there is no problems with the wiring to the right-hand side.