There’s a very interesting tug-of-war going on right now between Apple (AAPL) bulls and bears, specifically as it pertains to the upcoming Apple Watch. On one hand, bulls contend that the Apple Watch is going to be the next big hit for the tech giant. They have some ammunition working in their favor. Apple analyst Sherri Scribner, with Deutsche Bank, has estimated the Apple Watch to become an $26 billion business by 2018. This would provide Apple with valuable diversification away from the iPhone, which now represents the majority of Apple’s sales. On the other hand, Apple bears are very skeptical of the Apple Watch, and rightfully so. Consumer surveys show the Apple Watch losing some of its hype, and smart watches in general are not a major industry in the tech landscape. Of course, Apple has revolutionized industries before—and it just may again. However it works out, the Apple Watch is a major story in 2015 that investors need to keep their eyes on.