Despite the fact it's Bluetooth v2.1+EDR (it actually registers as a Qualcomm Atheros AR3011 HS v3.0 chip) with max. Speed of 3Mbps, it is a power Class 1 device with an amazing range of 100 meters (330 feet) line-of-sight in open space.

So, basically, it works uninterrupted in a decently sized bedroom and living room. My 'major' application of the device is to wirelessly stream all of the PC audio (movies/songs, etc.) over the bluetooth link to my bluetooth-enabled speakers. Over time, I noticed audio hiccups (not due to range or sync-related concerns) and primarily hang-ups of all media played over bluetooth. Researching the net thoroughly, I learned the ASUS BT211 is 'incompatible' with Windows 8/8.1. So, began my search for a latest Win 8/8.1 supported v4.0 Bluetooth LE adapter. After a month of research and convincing, I stumbled upon more than 'rave' reviews of the Kinivo BTD-300 and BTD-400 adpaters on Amazon and elsewhere. More importantly, the Kinivos are Microsoft-certified to work with Windows 8. However, when the Kinivo BTD-400 I bought arrived, the story was quite different. Firstly, it's a power Class 2 (not Class 1) device with a max. I spent hours, days trying lots of things/combinations to confirm the problem, before even invoking the Kinivo Customer Care and considering a replacement/return from/to Amazon: During scan, the Kinivo saw select devices: it saw my Note 2 with v4.0 LE, laptop with v2.1, but not a Logitech Bluetooth audio adapter/receiver with v3.0, etc.

Kinivo bluetooth driver bloatware