I got the new Fitbit Ionic a few weeks ago, and I'm generally pretty happy with the device. I'm in the process of writing a full review of the Ionic, but I realized partway through that I had written quite a lot about the SDK, which many people probably won't be interested in. Hence, I decided to make that into its own post. In the meantime, if you're looking for a review, I would recommend reading DC Rainmaker's. He's a much more serious athlete than I am, and he reviews fitness gear semi-professionally, so he's able to put the devices through much more rigorous tests and go into detail about things like heart rate and GPS accuracy, which I won't be doing.
Anyway, the Ionic being Fitbit's first real smartwatch, I was eager to check out the SDK and dive into app development. And, well, I've tried to do so, but so far the results haven't been great. I think this is partly just because the platform is very new, and partly because of some questionable technology decisions that Fitbit made. Although it's too early to really evaluate the success or failure of the Ionic, or of FitOS an app platform, I think it can still be instructive to look at some of the choices that Fitbit made in designing the device and the OS, what effects they're having on developers now, and why I think they may prove to have been suboptimal choices.
Battery life was clearly the foremost concern for Fitbit when they designed the Ionic, and the technology decisions reflect that. Whereas the Apple Watch series 3 has a dual core CPU with a maximum clock speed of at least 780 Mhz, 3D graphics acceleration, and a rumored 768MB of RAM, the Ionic contains the humble Toshiba TZ1201XBG, with a meager maximum clock speed of 120Mhz1. The battery life of the two devices reflects these hardware differences: the Ionic lasts 4-5 days on a charge, whereas the Apple Watch lasts a maximum of 2 days. Personally, I think this was a great choice by Fitbit. Although the Apple Watch is inarguably a more capable "smartwatch," its two-day maximum battery life is an absolute deal-breaker for me, which is one of the primary reasons I bought the Ionic instead.