I have tested Broadcomm versions 4 thru to 126.96.36.1990 on MS, Belkin, Logitech and CSR dongles.
I have also tested Toshiba V4.00.31 on all these.
Toshiba stack is by far the most stable on ALL of these dongles. My mouse and KB (Logitecg & MS) connect flawlessly everytime on computer start, my stereo bluetooth headset (Moto HT820) connects and the performance is superb. No static, drops or hisses. When I pause and resume, I always get the music. AVRCP profile works even after a pause of 30 mins.
I was having problems with V5xxxx of Broadcomm stack with my above devices.
My suggestion is to go for the Toshiba stack. There is a V4.00.36 available on: http://aps.toshiba-tro.de/bluetooth/pages/download.php
but it has copy protection for stereo Bluetooth devices (it will only pair to devices that conform to SCMS-T copy protection method). If a bright soul on this board is able to overcome that then this stack is stable and ideal for everyone's use.
As for V4.00.31 I have this, but in order to be useful you will have to modify the btwusb.inf equivalent file called tosrfusb.inf with yor devices VID and PID.
I am willing to upload V4.00.31 (32 bit only) to a common site; someone will have to tell me where and how.