I think in terms of hardware, Smart Watches are expensive. The Apple Watch Stainless is no exception at $600.00. That said, Apple's Products tend to last longer than others and the Apple Watch seems like it could have a long life ahead of it. I plan on keeping mine until Gen 3 Watch arrives. I own the regular and black stainless. I didn't purchase the Gen 2 Watch, being the exact same resemblance wasn't enough for me to spend another $600.00.
And the GPS and water resistance isn't enough to warrant an upgrade. But none the less, the Watch has picked up in popularity, which is both for fad and user preference with notifications/fitness.
You pay a premium for Apple products, but the payoff is Longevity and continued OS support (Hopefully).