Finally got this working with the Pebble. I've had the Pebble for over a year, but I could never get the Arduino->BlueSmirf combination to work.
I bit the bullet and wrote an iOS application to handle the watch communication. I'm a long way from finished on that front, but I've got enough functionality to say I really like the watch.
Since this is an iOS app, all the other watch functionality is present since it's paired with the phone. One of those features is the Misfit Shine fitness app(free activity tracker).
The BLE signal from the phone to the watch is strong. The watch receives updates from ~30 feet away. The metawatch is more like 10. Cranking up the bluetooth power wouldn't fix that, so I assume it's governed by antenna design.
The whole experience of setting up this watch is well done. It has a web based development environment, and there's allot of easily accessible information available for developers. Metawatch, meh.
Looking forward to adding an indicator on the watch to indicate "late" BG readings. I could never add this to the Metawatch without purchasing an IAR($3000) development license. It's also nice not having to map out my fonts, although I'll have to cook up some new arrows.
The iPhone is within 30 feet of me most of the time, so we'll see if this works for me.