Exactly right. The Cobra Tag uses traditional Bluetooth, so it has to be recharged every couple of days; we use Bluetooth low energy and a removable battery that lasts 6+ months. They don't support iPhone and we (currently) don't support Android.
I'd love to have this but it being iOS-only kills it for me. Any thoughts on opening up the spec? I'd love to implement this for both my laptop (Linux) and my Boot2Gecko phones.
It uses a custom UUID for advertising, but other than that it uses standard Bluetooth LE profiles for notification and battery status, so you should be able to do it...
These are both things you should see from PhoneHalo in the incredibly near future, AFAIK; sufficiently that I would not bother waiting for this other new product to maybe happen.