Samsung is showcasing its latest smartwatch, the Gear S2, at a consumer electronics show in Berlin. First impressions have been positive. But Samsung’s watch has plenty of competition in the wearables market, and a big disadvantage.

Analyst Ramon Llamas of IDC says that disadvantage is Samsung’s decision to use its own proprietary Tizen operating system, instead of Android Wear, to power the device. “It’s not a platform that droves and droves of developers are driving towards,” Llamas says.

Its reliance on Tizen is likely to make it harder for Samsung to attract a lot of popular apps for the watch. James McQuivey of Forrester research says in a nascent wearables market, apps are a key way in which consumers decide whether a product is useful enough to purchase.

“We’re seeing Apple Watch benefit from the attention given to it by Starwood Hotels [and] Foursquare, who are trying to make the watch basically a substitute phone,” McQuivey says.