[Aussie Mike]

There is one advantage with a cable not mentioned. You can set up a cable with an ecentric cam in the linkage. This will mean the pedal will be initially quite hard but once you get over the initial push the ecentric kicks in and effectively changes the pedal ratio. This makes the pedal relatively light when pressed all the way in so you aren't straining to keep it pressed.

If you've ever done any archery you will understand how it works. Modern compound bows use cammed pulleys that can give you 50% or more let off. This means you can draw a 55 to 60 pound bow and hold it for a couple of minutes till you are ready to take your shot. Keeping it drawn you are only holding 25 pounds. Do that with a similar recurve bow that's 55 pound at maximum draw and you would pop your pooper valve with the strain.

Just a thought.

Cheers