I own Samsung analogs. Mine are on about 40% Brightness anything more my retinas would flame out. why would i want more?
I should say I trade in a completely dark black room without light except from displays. Try it! No extraneous visual stimuli or distraction.. nothing but eerie GLOW of multiple displays (EIGHT of THEM) ... kinda like war room in a sub
Assuming that you guys are talking about TFT screens (Samsungs are very good): Over time the backlighting will fade and they'll get dimmer. I have got an IBM laptop that has been running 24 hours a day for 16 months and it is dimmer than when I first got it. Some screens can have their backlights replaced, others have it integrated with the screen and the whole screen needs replacing. Thus even if you have the same model, the brightness may not be the same, depending on usage. Peace