A:Answer The BenQ does have more Lumens (2,200 vs 1,800) and built-in speakers if moving it around is important to you (wasn't to me). But take a look at the below figures and you'll find out why it costs more. There were other things I factored in, but I researched these models heavily along with 3 other brands priced from $675 to $4,000 and bought the Sony HW45ES.
Contrast Ratio:
Sony HW45ES - 120,000:1
BenQ HT2150ST - 15,000:1
3D:
Sony - Yes
BenQ - No
Lens Shifting:
Sony - Yes
BenQ - No
Audible Noise:
Sony - 22.0dB
BenQ - 29.0 dB
Lamp Life:
Sony - 4,000 hrs. Ecomode increased this to 6,000 hrs
BenQ - 3,500 hrs
Warranty:
Sony - 3 yrs
BenQ - 1 yr