Why would the Exakta be slower to use ? Is use both systems Exakta Varex IIa and Nikon F and in my opinion they are equally fast. But then again I also somewhat prefer the ergonomics of the Exakta, which many people consider a disaster. Love the Nikon F and it's my main 35mm camera but the Exakta was already a full system including metering prism and up to 12sec exposure time, before the Nikon came to the market.

Dominik