Bluetooth accessory: how can I use a BT accessory (earpiece/wristband) to get text message alerts?

My wife and I both have iPhone 4S phones, AT&T. She is often in loud/busy places, and misses the sound and vibration for an incoming text. We're looking for a Bluetooth accessory that reliably notifies the user of incoming text messages (either a tone in an earpiece, or a vibration on a wristband). I've seen many earpieces with complaints that SMS/text notifications are missed -- for example, the Jawbone Icon has user feedback saying this feature has problems.

Does anyone have experience and firsthand knowledge they can pass on about which BT devices do this well?

Thank you.