Post del forer@ Murbella7 (por ejemplo) en la sección de comentarios de usuarios de Avforums.com tras una crítica del X3 realmente buena (en la que se explicita que su nivel de negros y contraste son de Referencia):

I have an X3 with over 750 hours on the clock. At around 700 hours, the lumens started to drop. I didn't really notice this until I hit the 730 hrs mark. At 750 hrs, the pic is almost unwatchable, even in the full/high output 3D mode. I did a Google on the issue and found reports in another forum.

Apparently the screen that sits in front of the lamp gets a 'foggy' film (probably like vinyl film on a car windscreen from the dash), over it after about 600 hrs. The owner in this forum had his unit replaced. Also I discovered that the lamp is guaranteed for just 3 months. So if you are only an occasional viewer, this issue may not show up until the lamp or even the entire unit is out of warranty.

No tengo tiempo de traducir, pero creo que se entiende.

Saludos.