Bluetooth Smart pairs in 3 ms which makes it feel like it’s always connected. The range of Bluetooth 4.0 Low Energy improves by over 50% over BT 2.1. I also like the latency which drops from 100ms in older version to 6 ms.

http://en.wikipedia.org/wiki/Bluetooth_low_energy

I don’t envision Bluetooth as being the proper protocol for any sustained streaming other than A2DP. I see it as finally being a good small device connection protocol. Eagerly waiting to see what Pogo’s Blue Tiger BT 4.0 pressure sensitive stylus can do on the new iPad

http://www.tenonedesign.com/bluetiger

It’s hard to believe that 4.0 will bring a dramatic difference.

In fact, according to what Wikipedia has to say. BT 4.0 / BLE won’t offer any savings for most common use cases, just the newer, bursty stuff like health monitor as mentioned.

“Note that the lower power consumption is not achieved by the nature of the active radio transport, but by the design of the protocol to allow low duty cycles, and the use cases envisaged. A Bluetooth low energy device used for continuous data transfer would not have a lower power consumption than a comparable Bluetooth device transmitting the same amount of data; indeed, it would likely use more power, since the protocol is optimised for small bursts.”

1. http://static.googleusercontent.com/external_content/untrusted_dlcp/www.google.com/en/us/events/io/2011/static/notesfiles/AndroidOpenAccessoryAPIandDevelopmentKitADK.pdf