I see that loft have done away with the x-ply at the top of their 2016 RBlade model. Durability wise I think this is a backward step but probably reduces production costs.
http://www.loftsails.com/products/sails/racing-blade 
We asked Monty to outline what's changed in the flagship 2016 Racing Blade range. What are the Key Developments? 'The plan form (outline), material change (more monofilm), leech tuning, tuned batten-taper and horizontal curve schedules - and new colors!' And the Benefits? 'Expand the wind range, improve stability, improve speed throughout the wind range . easier-to-access performance.' /images/misc/forum-image-missing.gif
How did you Achieve those Enhancements? 'Testing with my new Tarifa-based team - Ramon and Fernando - Monofilm proved to be faster than the 2-mm. x-ply used to build the 2015 Racing Blades. 'The mono test was conclusive: Racing Blades identical to each other EXCEPT for the material were tested against each other extensively. The result of our investigation concluded that monofilm produces improved performance. [oh and not to mention saves us a mint in production costs
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