... just to add my 2 cents.
I think yes its worth the upgrade if your going to ride surfboards or ride around in the surf.
I loved the 2011 Rebels, one of my all time favorites, best jumping kite for my heavy frame when on TT but had a tendancy to power spike when the kite shoots across the wind window when riding on waves with a surfboard. This power spike is perfect for jumping big but could pull you off a wave more often than not so was something you had to deal with easily.
When the 2014's came along I found it didn't have this big spike in power so it immediately felt easier to use in the surf but here's the ironic thing, it still jumped well. Seeing as I ride mostly surfboards now, it suited me better to have a lower power spike so I reckon if your going to ride in the surf, then 2014 will suit you better.
Anyway, just a thought,,, worth about 2 cents some would say!
cheers,
Robbie