Those were two separate photos...impossible to tell if brightness was really different or was camera exposure different between photos. Only way to show is to take one photo with both units at the same time.
Keypad backlight is not as bright as 996 (by design) but I'm not seeing big variations in brightness in the samples I'm checking. But, will continue to check.
I viewed two SDS-200(s) side by side today with the lights off in the room. Unfortunately, one unit had a very dim keypad back light; the other unit had a keypad that was barely lit at all, much worse than the other - big variation. Settings were verified; back lighting for the keypad was set to ON for both units. The units have serial numbers 1 number apart. The back light issue on the keypad is an actual, real problem. The brighter of the two units was marginally acceptable, but the dimmer unit was not acceptable at all and was clearly defective.
Half hypothesis, half fact's we already know: These units are mass produced on cheap labor assembly lines in Southeast Asia (Vietnam to be specific). I have to believe that quality control is lacking and parts used are not good quality (Captain Obvious, I know).
At this time I cannot recommend purchasing the SDS-200 due to personally observed variances with the keypad back light. If you do purchase, there is a significant chance you will need to return the unit.
On a side note, both units had the buzzing/humming noise coming from the speaker with the volume turned all the way down. The buzzing noise was not audible unless you put your ear to the speaker. I wasn't concerned about it on the units I tested. However, I do realize this is a bigger (louder) issue with other units.