[Joeboy]

In terms of the image, I think a big advantage Arri cameras have is a patent on simultaneous dual gain sensors. Perhaps somebody will tell me I've misunderstood that though.

Aside from that, I think a lot of what you pay for is reliability, support and general non-sketchiness, which are not areas where RED have a particularly good reputation.

[mtvkqn]

ARRI cameras have much better IR filters in front of the sensor. RED IR filters were horrible quality when we measured them, leading to worse image quality.

[erichocean]

Yup, precisely why comparing "stops" doesn't tell the whole story.

The Bayer color array also makes an enormous difference (and is unique to each manufacturer). Good ones are NOT cheap to make.