At $100 (£72 UK, or AU$141), this isn't a bargain. And the Misfit app, which handles basic steps, sleep and swim tracking, isn't nearly as good as Fitbit's. The Ray can become a smart button of sorts by linking to a separate Misfit Link app. But you need to triple-tap the metal tube to turn it into a single-purpose function: music remote, selfie shutter or one-function roles in a few connected apps supported by Misfit (Harmony, IFFT, Yo or Misfit's multihue Bolt light bulbs).
The Ray feels worse than the Shine 2 in some ways: While it has the same six-month or so battery life, its battery replacement system is awkward, involving unscrewing its tube and sliding batteries out. I ended up jamming mine and needing a paperclip. But the band stays on my wrist more securely, avoiding the pop-out problem the Shine 2 originally had for me (although a redesigned action clip solved those issues on Shine 2). Also, the Ray only has one glowing light, which doesn't do much. It loses the clever 12-LED design of the Shine, which showed activity progress in a ring and even the time with a simple tap, acting as a basic display.
I'd suggest a Fitbit instead. Or, look at a Pebble, which can track steps and sleep too...and is a watch...and even has a Misfit app. Or, consider that Fossil -- which acquired Misfit last year -- has many trackers that do similar things as well. Fossil has already promised hundreds of wearable products, many of them powered by Misfit technology. So, why choose Ray?
The age of high-design, minimal, single-purpose fitness accessories doesn't feel like it makes sense on my wrist anymore. Maybe you feel otherwise.