This may be the best read on this topic I have found. Thanks to all.
We are About to finish specifying our new boat
and this is one of the last big details to nail down. First I love the sail shape and reliability
of a slab full batten system for all the reasons previously mentioned but we are leaning towards IMF for all the reasons previously mentioned. What I will try to add and has only been mentioned in short is that not ALL IMF sails
are flat and with hollow leaches - there are some great looking IMF sails
with roach and reasonable depth
. We have sailed a similar example and performance/shape was Arguably better than the 3dis on our last boat.