Bluetooth vs Bluetooth Smart (Low Energy)
Bluetooth Low Energy is rated for 1Mbps, with a practical throughput of 305kbps. That's ~38 KILOBytes per second. It has a off to connected/transmiting latency of &lt;6ms, compared to bluetooth classic of ~100ms. It saves energy by only being on when actually transmitting data, instead of keeping the link active as you would with Bluetooth Classic.

When you are talking about BLE being inefficient at continuous data transfer, it is in relation to streaming data in the range of hundreds of kilobits, i.e. audio or video. You are using less than 10% of the maximum transfer rate. BLE should be very well efficient for your intended purpose. 20 packets per second is a very very small amount of data.

Refs:
http://www.medicalelectronicsdesign.com/article/bluetooth-low-energy-vs-classic-bluetooth-choose-best-wireless-technology-your-application

http://www.bluegiga.com/files/bluegiga/Pub%20files/Bluetooth_LE_comparison.pdf