Wearables for Cycling: Something Good Will Surely Evolve, but as for Now...
I still think my SRM head unit is the cat’s meow... runs for 200 hours on a charge, huge storage, no power-sucking GPS, and no special glasses or other crap needed, all with accuracy to within 1% for watts/KJ/KCal at a weight far less than any iPhone. And I can wear my usual excellent REVO sunglasses.