i went through a lot of research when trying to decide for a BT USB Adapter.
I was vary of the cheaper ones as their specs were not always what was advertised.
I was looking for a BT Adapter that had:
.Bluetooth 2.0 (cuz my phone is 2.0 too)
.EDR (enhanced data rate ~3mbps)
.Class 1 Operation 100m range
this is usually the parameter that is falsely advertised in cheaper brands. be aware that your device on the other end of the BT communication should also be class 1 to actually utilize class 1 operation. most phones are not, some headphones these days are.
.Widcomm BT Stack (Broadcom)
oldest BT Stack and easy to develop with, hence a lot of ppl use it to make apps with.
.A2DP & Audio Gateway Profile: Allows me to use my PC as a stereo wireless headset for my phone without any other software.
Apart from the above, I also like the BT ActiveSync for my phone and the ability to share my phone's internet connection via BT
Anyways, so my choice of BT Adapters that fit the bill was an MSI Starkey 2.0 USB adapter.
http://www.msicomputer.com/product/p..._2.0&class=com
cost me almost 40bux on ebay, pricey compared to the $10 ones, but worth it i think.