I finally fitted the old autoprop to our Passport 51 and now have the stats from 2 season of crusing one with fixed 3 blader, one with Autoprop.
With AP we do same speed at 60% of revs and therefore have averaged 4.2 litres per hour rather than 6.4 previously.
Boat handling the same as the fixed, possibly slightly quicker stoping but marginal.
I have always doubted the benefits of less drag from folding props especially on a boat that fully laden weighs nearly 24 tons. However to my total astonishment we have gained 0.75 - 1 knot
of boat speed since fitting it, so we can now sail in 8-10 knots of wind
when before we needed 12+ and in the trades we are doing 8.5 rather than 7.5 quite a difference!
This only compares an AP to a fixed prop, so no help in the debate of which is the better folding prop, but in summary I think it's great.